B3277GS Pressure Washer Pumps by Generac

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BRIGGS & STRATTON CORPORATION Milwaukee, WI 53201 Part No. B3277GS Rev. 0 11/98 Printed in U.S.A.

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Electronic Version #B3277 Rev. 1 4/03

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Pressure Washer Familiarization & Troubleshooting Guide

FORWARD This guide has been written and published by Briggs & Stratton Corporation to aid our dealers' mechanics and company service personnel when servicing the products described herein. It is assumed that these personnel are familiar with the servicing procedures for these products, or like or similar products, manufactured by Briggs & Stratton Corporation. It is also assumed that they have been trained in the recommended servicing procedures for these products, which includes the use of mechanics hand tools and any special tools that might be required. Proper service and repair is important to the safe, economical and reliable operation of all engine driven systems. The troubleshooting, testing, service and repair procedures described in this guide are effective methods of performing such operations. We could not possibly know of and advise the service trade of all conceivable procedures or methods by which a service might be performed, nor of any possible hazards and/or results of each procedure or method. We have not undertaken any such wide evaluation. Therefore, anyone who uses a procedure or method not described by the manufacturer must first satisfy himself that neither his safety, nor the safety of the product, will be endangered by the service or operating procedure selected. All information, illustrations, and specifications contained in this guide are based on the latest production information available at the time of publication. However, Briggs & Stratton Corporation reserves the right to change, alter, or otherwise improve the product at any time without prior notice. Some components or assemblies of the product described in this guide may not be considered repairable. Disassembly, repair and reassembly of such components may not be included in this guide.

Copyright © 2003 Briggs & Stratton Corporation All rights reserved.

No part of this material may be reproduced or transmitted, in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without prior permission in writing from Briggs & Stratton Corporation.

Portable Pressure Washer Familiarization and Troubleshooting Guide Table of Contents

TABLE OF CONTENTS 1 • Operation 2 • Pressure Washer Components

5

7

4 • Small Frame Electric Pump

17

Part 1 - Specifications and Views Performance Specifications

17 17

Cross-Sectional View

18

Exploded View

20

Power Source

7

Pressure washer pumps

7

Inlet and Outlet Check Valves

8

Unloader - Pressure Regulator

8

Thermal Bypass System

9

Pump Head

22

Chemical Injection

9

Piston Housing Removal

23

Easy Start Valve

10

Piston Housing Disassembly

24

High Pressure Hose

11

Chemical Injection System

24

Spray Guns

11

Auto Start Switch Assembly

25

Spray Wands and Nozzles

12

Axial Cam

26

3 • General Information Part 1 - General Maintenance Chemical Injection System

Part 2 - Disassembly General Information & Special Tools

13 13 13

Inlet Water Supply Connector

13

Inlet Supply Filter/Strainer

13

Hose, Spray Gun and Wand Systems

13

Spray Nozzle Servicing

14

Part 2 - Lubrication Check Pump Oil Level

15 15

Change Pump Oil

15

Part 3 - Storage Pump Storage

16 16

Protection Against Freezing

16

Purging Air From the System

16

Part 3 - Inspection Seals, O-Rings, and Gaskets

27 27

Piston & Spring Assemblies

27

Pump Head and Piston Housing

27

Axial Cam Drive Components

28

Part 4 - Reassembly Pump Head Assembly

29 29

Auto Start Switch Assembly

29

Chemical Inject Assembly

30

Piston Housing Assembly

31

Pilot Spacer Installation

31

Pump Head Bolts

32

Assemble Axial Cam

32

Oil Fill

32

Main Component Assembly

32

Final Assembly and Test

33

Part 5 - Troubleshooting

1

22 22

34


TABLE OF CONTENTS Small Frame Gas Pump Part 1 - Specifications and Views Performance Specifications

35


35 35

56 56

Pump Head

56


57 57

Cross-Sectional view

36

Exploded View

38

Pistons and Piston Springs

40 40

Pump Head

58

Spacer Plate

58

Inlet Check Valves

59

Outlet Check Valves

59

Unloader Spindle Assembly

59


60

Thermal Bypass Actuator Removal

60

Part 2 - Disassembly General Information & Special Tools Pump Head

40

Piston & Unloader Housing Removal

40

Piston & Unloader Housing Disassembly

41


42

Unloader

42

Engine Adapter

43


43 43


43

Engine Adapter, Pump Head and Piston/Unloader Housing Axial Cam Drive Components

61

Check Valves

61

Head Gasket

61

44

Engine Adapter O-Rings

62

44

Engine Adapter, Pump Crankcase and Spacer Plate/Head

62


62


62

High Pressure Outlet/Chemical Injection Assembly

63

45 45

Unloader Assembly

45

Chemical Injection Assembly

45

Piston & Unloader Housing Assembly

46

Pump Head Assembly

46


47

Pilot Spacer Installation

48

Pump Head Bolts

49

Oil Fill

49

5 • Medium Frame Pump Part 1 - Specifications and Views Performance Specifications

61 61

Seals

Part 4 - Reassembly Engine Adapter




50

51 51 51


52

Exploded View

55

Piston Oil Seals and Pistons

65

Spacer Plate

67

High Pressure Seal Assembly

67

Check Valve Assembly

68

High Pressure Outlet and Chemical Injection Assembly

69

Unloader Spindle Assembly

69

Pump Head Installation

70


71

Oil Fill

72

Part 5 - Troubleshooting 2

64 64

73


TABLE OF CONTENTS 6 • Large Frame Pump Part 1 - Specifications and Views Performance Specifications

75 75


76

Exploded View

78


80 80

Pump Head

80

Axial Cam Drive Components (Tapered Engine Shaft)

81

Axial Cam Drive Component (Straight Engine Shaft)

82

Pistons and Piston Springs

82

Regulator/Unloader Valve

82

Cylinder Head

84

Thermal Bypass Actuator Removal

85

Spacer Plate

86



75

Oil Seals

87

Inlet Check Valve Seals

87

Outlet Check Valve Seals

87

Head Gasket

88

Engine Adapter Gasket

88

Engine Adapter, Pump Crankcase, Spacer Plate and Head

88


88


89

Unloader-Pressure Regulator Valve

90

Piston Oil Seals and Pistons

94

Spacer Plate

96

Pump Head Assembly

96

Pump Head Installation

98

Unloader-Pressure Regulator Valve

99


99

Oil Fill

101


102

Glossary

87 87

3

91 91

105


4

Pressure Washer Familiarization and Troubleshooting Guide Section 1 • Operation

PRESSURE WASHER OPERATION Operation of a pressure washer system may be briefly described as follows. Please refer to Figure 1.1 for visual component identification:

2. Rotary motion of the motor crankshaft is converted to reciprocating motion of the pump’s pistons using an axial cam.

1. An inlet hose delivers water to the motor-driven, pistontype pump. An inlet strainer (item 6) protects the pump (item 5) against damage from solid impurities. The motor driving the pump (item 9) may be gas or electric.

On a piston’s ‘suction’ stroke, an inlet valve opens and water is drawn into the piston chamber. On the piston’s ‘pressure’ stroke, that piston’s inlet check valve closes and its outlet check valve is forced open so pressurized water can leave the chamber. There is one inlet check valve and one outlet check valve for each piston.

Figure 1.1 — Example Pressure Washer System

Item 1 2 3 4 5

Name Spray nozzle Hi-Lo nozzle collar Spray gun extension wand Spray gun with locking trigger Pump, including optional thermal relief and/or easy start valve

Item 6 7 8 9 10

5

Name Inlet strainer Unloader/pressure regulator valve Chemical inject fitting (optional) Engine on cart High pressure hose

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 1 • Operation

3. The linear movement of the pistons pump a fixed volume of water through the pressure washer system. The volume of water flow depends on

9. The optional chemical injection assembly (item 8) permits detergents or other chemicals to be drawn into the water stream and (along with the water) discharged from the nozzle.

a. piston diameter

10. The nozzle collar (item 2), a part of the spray gun nozzle, permits easy selection of high or low velocity spray or a fan or stream spray pattern.

b. length of piston stroke c. number of pistons d. number of piston strokes per minute.

11. An optional easy start valve relieves pump outlet pressure during cranking for quicker and easier starts.

4. The pressure that builds up in the system then depends on the size of the spray nozzle orifice (item 1).

12. As a nozzle is used, it often becomes clogged with various types of matter. A clogged nozzle obstructs the water flow causing a reduction in outlet pressure. It also may cause the water stream to pulsate while the gun is triggered. Therefore, the nozzle should be checked and cleaned before every use, using the cleaning kit provided with every Generac Portable Products® pressure washer system.

5. The fixed volume of water flows past an unloader/pressure regulator valve (item 7), an optional chemical injection assembly (item 8), through a highpressure hose (item 10), and to a spray gun (item 4). 6. The spray gun permits the operator to turn the flow of water on or off. 7. If the water flow is turned off, water pressure within the pump will increase until the unloader/regulator valve (item 7) is moved off its seat. Flow is then bypassed back to the pump inlet through an internal bypass channel. Fluid bypass continues as long as the spray is turned off.

13. The flow of water through the nozzle will gradually wear away the nozzle orifice, causing the orifice to become larger. This enlargement will eventually cause a reduction in system pressure. For this reason, the nozzle should be replaced periodically and always replaced with the correct nozzle.

8. Recirculating bypass water can become hot enough to damage seals and other pump parts. Some pressure washer systems may be equipped with an internal thermal relief valve which automatically replaces hot water with cool water.

6

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 2 • Pressure Washer Components

PRESSURE WASHER COMPONENTS Power Source

Figure 2.1 — Pressure Washer Pump

Generac Portable Products® uses several engine manufacturers and different pump types on its pressure washers. Generac Portable Products® also uses an electric motor on some models.

The motor horsepower rating is designed into the overall rating of the pressure washer. Pressure pumps require a specified amount of horsepower for the pressure rating of the pump. It is important to remember that engine performance may be miss-diagnosed as a failed pump, and a failed pump may also be miss-diagnosed as a faulty engine. This manual does not cover service and repair of the engine. Refer to the engine manufacturers’ service manual for engine repair specifications.

Pressure washer pumps Generac Portable Products® pressure washer pumps are positive displacement, piston type pumps. They use an axial cam to impart a reciprocating motion to its three (3) pistons. The volume of water moved by the pump depends on:

Item

Name

1

Pressure adjust knob

2

Thermal bypass actuator

3

Inlet check valve

4

Garden hose connector/strainer

5

Thermal bypass outlet

6

Axial cam

7

Engine drive shaft

4. The number of pistons

8

Engine adapter bearing assembly

Theoretically, a pump will always move the same volume of water, regardless of flow restrictions.

9

Piston shoe bearing assembly

10

Piston spring retainer

The pump’s axial cam is coupled to the engine crankshaft, so that it revolves at the same speed as the engine. Figure 2.1 depicts a simplified cross-sectional diagram of a typical pressure washer pump mechanism.

11

Piston return spring

12

Piston

13

Outlet check valve

14

High pressure discharge port

1. The axial distance each piston moves on its pressure stroke 2. The diameter of each piston bore 3. The rotating speed of the axial cam (RPM of the engine or electric motor)

If the pump simply discharges water to atmosphere, no pressure will be created. A pressure buildup in the system occurs when flow is restricted downstream from the pump. By adding a nozzle to the system, pressure will increase to force the same volume of water through the nozzle orifice. The smaller the nozzle orifice, the greater the pressure needed to force the pumped volume through the nozzle.

7


Inlet and Outlet Check Valves

Unloader - Pressure Regulator

A set of six (6) inlet and outlet check valves work in conjunction with the pump pistons to create volume flow. As a piston is moved toward the axial cam by its return spring during its suction stroke, that piston’s inlet check valve opens and allows water to enter the pumping chamber. During the suction stroke, that piston’s outlet check valve is forced closed, as depicted in Figure 2.2.

Output water pressure can be adjusted using the pressure adjust knob on the Unloader-Pressure Regulator assembly. Turn the knob clockwise to increase pressure (up to the rated maximum pump pressure), counterclockwise to decrease pressure. The pressure washer is provided with an unloader pressure regulator valve to protect the pump and hose system whenever water flow is blocked upstream. Blockage is caused when the spray gun trigger is normally closed or by a kinked pressure hose or a clogged nozzle. Without an unloader system, water pressure could increase until the engine stalls or part of the system ruptures to relieve the pressure.

Figure 2.2 — Inlet Check Valve - Suction Stroke

As shown in Figure 2.4, the unloader valve will open at a preset maximum pressure to divert all or part of the flow back to the pump inlet. During such shutdown conditions, the water will circulate from the pumping chambers to the pump inlet and then back to the pumping chambers. Figure 2.4 — Typical Unloader - Pressure Regulator System

Item

Name

1

Inlet check valve

2

Outlet check valve

When the piston is pressed forward by the axial cam on its pressure stroke, its inlet check valve is forced closed and its outlet check valve is forced open, as seen in Figure 2.3. Figure 2.3 — Outlet Check Valve - Pressure Stroke

8


Thermal Bypass System

Figure 2.6 — Low Pressure Suctionof Chemical Injection System

When the trigger on the gun is not squeezed, the water in the pump is recirculating and under pressure. This condition causes the water in the pump to become hot. Excessively hot water may cause damage to the pressure washer pump elements. To resolve this problem, some Generac Portable Products® pressure washers are equipped with a thermal bypass system. Figure 2.5 depicts components of such a system. Figure 2.5 — Thermal Bypass System

Item

Name

1


2

Thermal bypass actuator stem

3

O-ring

4

Thermal bypass piston

5

Thermal bypass spring

At a water temperature of approximately 140°F, the thermal actuator stem will push the thermal piston off its seat. Heated water will then bleed out of the pump to the ground. As cool water enters the pump, the thermal actuator stem retracts and the thermal piston closes against its seat, halting the water bleed-off.

Item

Name

1

Venturi o-ring

2

Spring

3

Check ball moved OFF valve seat

4

Chemical injection fitting

5

Chemical injection venturi

6

Discharge port

7

Chemical solution reservoir

8

Siphon tube strainer

9

Chemical siphon tube

As low-pressure water flows through the injector venturi throat, its velocity increases and its pressure decreases. The suction created by the low pressure at the venturi throat draws the liquid chemical through a strainer into the siphon tube, around and past the spring-loaded ball, through small orifices in the venturi, and into the water stream.

Chemical Injection Generac Portable Products® pressure washers commonly incorporate a means of adding wax or cleaning/sanitizing chemicals into the low-pressure water stream. As depicted in Figure 2.6, the chemical injection assembly includes a venturi, a spring-loaded ball and seat, a chemical siphon tube, and a strainer.

Chemical injection only operates at the low pressure setting because detergents and chemicals require some soak or residence time on the surface to be cleaned. Low pressure also avoids splashing, over-spraying, and waste.

9


Easy Start Valve

When the pump is in the high pressure mode, the chemical injector ball is forced against its seat, cutting off the siphon effect and preventing water from back-flowing into the chemical reservoir. Figure 2.7 depicts this high pressure condition.

Certain larger Generac Portable Products® pressure washers may be equipped with an easy start valve. This patented device relieves pump outlet pressure during engine cranking so that it is easier for an individual to pull the recoil starter rope.

Figure 2.7 — High Pressure Cut-off of Chemical Injection System

Figure 2.8 depicts a Generac Portable Products® medium frame pump in its starting condition. Inlet water is connected to the pump’s garden hose connector. Air has been purged from the pump’s water passages. The check ball is attached to its restraint magnet (magnet not shown). Figure 2.8 — Starting Condition

Item

Name

Item

Name

1

Location of restraint magnet (not shown)

1

Ball shown seated, cutting off chemical flow

2

Check ball shown attached to magnet

2


3

Inlet water channel

3

Siphon tube

4

Check ball seat

5

Venturi throat

In this condition, the pump’s internal water pressure is at garden hose pressure. Water is free to circulate throughout the pump without restriction, thus permitting an easier pull on the starter rope.

The chemical injector must be carefully sized for the system. Too small of a venturi orifice will result in too low a pressure and too much chemical will flow into the stream. Too large an orifice will cause too much pressure at the venturi throat and the injector will not work.

As soon as the engine starts, water flow forces the check ball against its seat, closing the garden hose pressure water passage. Pressure within the system becomes regulated by the unloader valve setting and the nozzle restriction.

10


High Pressure Hose

Bypass refers to the direction of fluid flow as the water recirculates through the pump. Bypass occurs when the normal flow of water through a nozzle is shut off.

Generac Portable Products® uses excellent quality high pressure hoses appropriate for each pressure washer model. Hose length, hose internal diameter, and hose pressure rating are all factored into the overall design of the pressure washer system.

Figure 2.9 depicts the pump in the bypass condition with the engine running and the spray gun trigger released. Figure 2.9 — Bypass Condition

Item

Name

1

Outlet pressure water stream

2

Trapped line pressure piston shown in closed condition

3

Easy start check ball OFF its seat

4

Unloader piston assembly

5

Inlet water channel

Hose specification factors include: gallons per minute rating of the pump, pressure rating of the pump, and pressure drop over the length of the hose between the pump and the spray gun. Additional factors may also be used. Accessory hoses are available to lengthen the hose from its stock length. Generac Portable Products® does not recommend exceeding a total length of 100 feet between pump and nozzle because excessive length may adversely affect chemical injection and adequate high pressure operation.

Spray Guns Generac Portable Products® uses several types of spray guns for different model pressure washers. A diagram of a typical spray gun with the trigger closed is seen in Figure 2.11. Figure 2.11 — Typical Spray Gun Mechanism

Figure 2.10 depicts the pump in a normal operating condition with the engine running and the spray gun trigger depressed. Figure 2.10 — Normal Operating Condition

Item

Name

1

Outlet pressure water stream

2

Trapped line pressure piston shown in open condition

3

Easy start check ball against its seat

4

Unloader spindle assembly

5

Inlet water channel

11

Item

Name

1

High pressure inlet connector

2

Spray gun body

3

Valve body

4

Valve return spring

5

Check ball

6

Check ball valve seat

7

Wand body

8

Trigger

9

Safety latch in lock position


Spray Wands and Nozzles

Pulling back on the trigger moves the spray gun check ball off of its seat, as shown in Figure 2.12. The water then flows through the open valve and out of the wand to the nozzle.

The spray nozzle is critical to proper operation of a pressure washer. The nozzle restricts the liquid flow and allows the required pressure to develop. The smaller the nozzle orifice, the higher the system pressure. Use of a nozzle having too large an orifice will result in a reduced system pressure.

Figure 2.12 — Spray Gun - Trigger Open

In addition to establishing system pressure, the nozzle breaks the liquid into droplets, forms the spray pattern, and propels the liquid in the proper direction. Several different types of spray nozzles may be used. The most popular type provides adjustable pressure and spray patterns. For Generac Portable Products® nozzles, slide the nozzle backward for High Pressure spray; push the nozzle forward for Low Pressure spray; twist the nozzle clockwise for a Fan Spray Pattern; and twist the nozzle counterclockwise for a Narrow Stream. In addition, Generac Portable Products® offers several accessory nozzles, such as a rotating brush, utility brush, and turbo nozzle.

DANGER: Do not attempt to adjust pressure or spray pattern while spraying. Never place your hand in front of the spray nozzle to adjust pressure or spray pattern. Refer to the Owner’s Manual for the specific pressure washer model for correct operating instructions.

When the trigger is released, the valve shuts against its seat and the water flow is stopped. This condition causes the pump to enter the bypass mode.

CAUTION: Spray guns and wands are rated for maximum pressure and flow rate. Use of an incorrect spray gun and wand can be dangerous and will adversely affect pump performance. If replacement becomes necessary, you must replace the gun as an assembly. Use only the spray gun and wand listed in the “Repair Parts” section of the owner’s manual for the specific pressure washer model being serviced.

12

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 3 • General Information

GENERAL INFORMATION Part 1 - General Maintenance

the strainer or replace it if it is damaged, torn, or perforated. Reassemble the connectors, using petroleum jelly as necessary to ease the connections.

This section describes the general maintenance procedures recommended for pressure washer components that are common across product lines.

Figure 3.2 — Inlet Supply Strainer

Chemical Injection System Before each use, inspect the chemical injection suction hose strainer. Clean as necessary, or replace if damaged, torn or perforated. Examine the chemical suction hose and replace if damaged. Rinse the chemical injection system thoroughly after each use by siphoning several pints of clean water through the system. Inlet Water Supply Connector The pressure washer may be equipped with a “Quick Disconnect” type connector for convenient attachment of the inlet water supply. This type of connector, depicted in Figure 3.1, operates easily if the o-ring is periodically lubricated with a petroleum jelly. Figure 3.1 — Quick-Disconnect Hardware

Hose, Spray Gun and Wand Systems With the pressure washer OFF, inspect the hose connection to the spray gun. Make sure it is tight. Test the trigger by squeezing it and making sure it springs back to the OFF position when released. Set the safety latch to ON and and test the trigger, making sure the trigger cannot be squeezed. With the pressure washer ON and the trigger latched OFF, verify the absence of leaks from the spray gun. With the pressure washer OFF, inspect the high pressure hose for cuts, leaks, abrasions, bulging, kinking, or abuse. With the pressure washer ON and the trigger latched OFF, verify the absence of leaks from the hose.

DANGER: Water spraying from a leaking hose can inject material into the skin or cause serious injury. Never attempt to repair high pressure hoses. Replace the hose with a high quality hose that meets the minimum pressure rating recommended by the manufacturer.

The water supply quick-disconnect must be correctly installed on the supply hose and the pressure washer or its inlet supply filter will not be effective. Inlet Supply Filter/Strainer Remove the quick disconnect from the hose and inspect the inlet water strainer. It should be oriented so that the pointed part (the screen) points away from the pump (towards the garden hose).

An o-ring maintenance kit for each model is available to refurbish all connection seals.

A typical inlet supply connection is seen in Figure 3.2. Clean 13


Spray Nozzle Servicing If the spray nozzle becomes clogged with dirt, excessive pump pressures may develop. A nozzle that has become partly clogged will demonstrate a ‘pulsing’ sensation during use. If the nozzle becomes clogged or partially restricted, it can be cleaned as follows:

6. Remove any additional dirt from the wand by backflushing with water, as described below and shown in Figure 3.4. Figure 3.4 — Back-flushing the Wand

1. Shut down the engine and turn off the water supply to the pump. 2. Put on your safety glasses, as there could be trapped pressure behind a totally-clogged nozzle. 3. Disconnect the wand from the spray gun. 4. As seen in Figure 3.3, use a 5/64 inch (2mm) Allen wrench to remove the nozzle from the end of the wand. 5. Use a length of wire similar to that seen in Figure 3.3 to free any dirt from the nozzle. Figure 3.3 — Nozzle Removal and Cleaning

a. Hold the water supply against the wand and back-flush for about 30 seconds to 1 minute. b. While flushing, move the nozzle collar between stream and spray positions and between the low and high pressure positions. 7. Use the 5/64 inch (2mm) Allen wrench to reinstall the nozzle into the wand. DO NOT OVERTIGHTEN. 8. Reattach the wand to the spray gun. 9. Reconnect the inlet water supply to the pump and turn on the water. 10. Start the engine and test operation.

NOTE: If desired, a 5/64 inch (2mm) wrench can be ordered by specifying Generac® nozzle kit part number 96961. A length of 17 gauge (0.039 inch) wire may be used to clean the nozzle. If desired, a nozzle cleaning rod may be ordered by specifying Generac® nozzle kit part number 96869.

14


Part 2 - Lubrication

Always check pump oil level with the unit resting on a level surface. Oil should be at the full mark on the sight gauge (near the center). On units equipped with an oil dipstick, oil level should be near the full mark. Add recommended pump oil as required, to the full mark only.

All pressure washers require oil lubrication of the piston mechanism in order to maintain long-term reliability and service. Certain early model Generac Portable Products® pressure washers incorporate sight glasses or dipsticks to be used to monitor pump oil levels. Later Generac Portable Products® models have improved designs that eliminate the need to routinely monitor oil levels or to change lubricating oil.

Change Pump Oil

WARNING: DO NOT change pump oil unless the pressure washer Owner’s Manual requires this AND your pump is equipped with a pump drain plug.

This section describes how to check and change pump oil on early Generac Portable Products® pressure washer systems. If servicing a non-Generac Portable Products®-manufactured pump, please refer to the maintenance instructions provided with that specific system.

Please refer to the maintenance instructions that were shipped with your non-Generac Portable Products®-manufactured pump if it is necessary to change pump oil. Pay particular attention to the manufacturer’s recommended torque values when tightening drain plugs and breather/dipstick caps.

Check Pump Oil Level Certain pressure washers may be equipped with a glass sight gauge, as depicted in Figure 3.5.

To change oil in Generac Portable Products®manufactured pumps, refer to Figure 3.5 and proceed as follows:

Figure 3.5 — Sight Gauge on Side of Pump

1. Place a suitable container under the pump drain plug. 2. Remove the oil fill cap (breather cap) from the top of the pump. 3. Remove the pump drain plug from the bottom of the pump. Drain oil completely into the container. 4. When all oil has drained, reinstall the pump drain plug and tighten to the torque value specified in the Torque Chart, found on the exploded view in the chapter for your pump. 5. Insert a funnel into the oil fill cap opening and add the recommended oil until the oil level reaches the full mark. Oil capacity and type is listed in Part 1, earlier in Section 3. 6. When oil is at the proper level, install and tighten the oil fill cap to the torque value specified in the Torque Chart, found on the exploded view in the chapter for your pump.

Item

Name

1

Breather cap/oil fill location

2

Drain plug

3

Sight gauge location

15


Part 3 - Storage

Protection Against Freezing To protect the pump against freezing, proceed as follows:

Pump Storage Water should not be allowed to remain in the pump for long periods of time. Sediment can become deposited on pump parts, resulting in pump ‘freeze-up’.

1. Draw automotive windshield washer fluid into the pump: a. Connect a three (3) foot length of garden hose to the pump inlet.

To protect the pump against water sediment buildup, proceed as follows after each use:

b. While holding the open hose end higher than the pump, pour the washer fluid into the length of hose.

1. If the chemical injection siphon was used, flush the system as follows:

c. With the engine RUN/STOP switch in the STOP position, pull the engine’s recoil starter handle two or three times. This should replace most of the water in the pump with anti-freeze solution.

a. While running the pressure washer with the nozzle set to low pressure mode, place the chemical siphon tube and its strainer into a pail of clear water. b. Permit siphon action to continue for two or three minutes to flush the system.

Purging Air From the System Prior to use, the pressure washer pump, hose, and spray gun should be purged of air. To do this, proceed as follows:

c. Shut off the engine and let it cool. Squeeze the spray gun trigger to relieve trapped line pressure. Then remove all hoses.

1. Prepare the pressure washer for use as outlined in the Owner’s Manual. Make sure a proper water supply is connected and turned ON. 2. Put on your safety goggles and remove the wand from the spray gun.

WARNING: Never start the engine or operate the pump unless the proper water supply is connected. Any attempt to run the pump without the correct water supply will result in damage to the pump.

3. Pull the trigger on the gun and hold open. 4. When the water flow is steady and constant, release the trigger to turn off the flow. 5. Reattach the wand to the gun.

2. With the engine RUN/STOP switch in the STOP position, pull the engine’s recoil starter about six (6) times. This should remove most of the liquid from the pump.

The system is now ready for use.

3. Drain water from the high pressure hose, then coil the hose and stow it properly. 4. Store the unit in a clean, dry area.

16

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 4 • Small Frame Electric Pump

SMALL FRAME ELECTRIC PUMP This section describes the small frame pump assemblies powered by electric motors. This small frame electric pump may also be referred to as ‘EE’ or ‘GPW-EE’ or ‘Economy Electric’ pumps. The small frame electric pump has the following features: • 1100 to 1300 PSI water pressure • 1.5 to 1.8 Gallons per minute flow • Axial Cam Design • Stainless Steel Pistons • Fixed Pressure Unloader • Chemical Injection System or Foamer Bottle available • Grip-Start™ - Automatically turns on the pump when spray trigger is pressed • Safety Flow™ switch - Pump will not operate unless water supply is turned on. • Oil bath, helical gear drive system • 14 Amp Universal motor • Designed to UL 1097 Double Insulation standards

Part 1 - Specifications and Views Performance specifications for Generac Portable Products® small frame electric pumps, sectional and exploded views, and a table showing recommended torque values are provided below. Model Part No.

Rated Pressure+

Pump Head

Flow Rate*

Piston Material

Oil Type/ Capacity

0762-0 0776-0 0766-1 0793-0 1007-0 9606-0 9737-0

1250 1300 1250 1250 1250 1100 1150

Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum

1.5 1.5 1.5 1.5 1.5 1.8 1.8

Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel

80W90/60ml 80W90/60ml 80W90/60ml 80W90/60ml 80W90/60ml 15W40/150ml 15W40/150ml

Performance Specifications + Pressure (in pounds per square inch) is adjustable up to the unit's rated pressure. * Flow rate is given in gallons per minute. Pump assemblies are listed by part number and were current at time of publication. Other pump assemblies will become available as our products evolve.

17

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 4 • Small Frame Electric Pump Cross-Sectional View

A typical small frame electric pump is shown in Figure 4.1 in cross-section.

Figure 4.1 — Small Frame Electric Pump (cross-sectional view)

18


Cross-Sectional View Parts List Item

Qty.

Description

Item

Qty.

Description

1

1

O-ring

26

3

High pressure water seal

2

4

O-ring

27

4

Lock washer, M6 ribbed

3

1

Shuttle valve spring

28

4

SHCS M6- 1.0 x 35mm

4

1

Shuttle valve

29

3

Piston

5

3

O-ring

30

1

Pump head

6

3

Outlet port check valve cap

31

3

Inlet check valve

7

1

Tie wrap

32

3

Outlet check valve

8

2

O-ring

33

1

9

1

Motor assembly, complete

Hex socket set screw w/ Locktite DO NOT REMOVE

10

1

Motor cover housing

34

1

Taper plug DO NOT REMOVE

11

1

Housing and switch assembly

35

1

Pop off valve spring

12

1

Foam air filter

36

1

Pop off valve ball seat

13

1

Axial cam idler shaft

37

1

Pop off valve check ball

14

2

Bearing washer 35 x 55 x 3mm

38

1

O-ring

15

1

Needle thrust bearing 35 x 52mm

39

4

Rubber mount

16

1

Axial cam/gear assembly

40

2

Taptite screw, M4-0.7x10mm

17

1


41

4

Plastite screw, 6-19 x 0.75”

18

1


42

1

Backup ring

19

3

SHCS M6-1.0 x 20mm

43

1

O-ring

20

1


44

1

Auto switch piston return stop

21

3


45

1

Auto switch piston return spring

22

1

Piston housing

46

1

Auto switch piston assembly

23

3


47

1

Backup ring

24

3

Oil seal

48

1

Retainer cap

25

3

Pilot spacer

49

1

Auto switch grommet

50

1

Auto switch

51

1

Auto switch housing

19


Exploded View

A typical small frame electric pump is depicted in exploded view in Figure 4.2.

Figure 4.2 — Small Frame Electric Pump (exploded view)

Item

Torque Value

6

15-17 ft-lbs

19

7-9 ft-lbs

28

9-12 ft-lbs

33

9-12 ft-lbs

40

2-4 ft-lbs

41

2-4 ft-lbs

48

10-12 ft-lbs

54

Brass: 15-23 ft-lbs Nylon: 10-12 ft-lbs

57

20-30 in-lbs

20


Exploded View Parts List Item

Qty

Description

1

1

O-ring

2

4

O-ring

3

1

Shuttle valve spring

4

1

Shuttle valve

5

3

O-ring

6

3

Outlet port check valve cap

7

1

Tie wrap

8

2

O-ring

9

1

Motor assembly, complete

10

1

Motor cover housing

11

1

Housing and switch assembly

12

1

Foam air filter

13

1


14

2


15

1


16

1


17

1


18

1


19

3

SHCS M6-1.0 x 20mm

20

1


21

3


22

1

Piston housing

23

3


24

3

Oil seal

25

3

Pilot spacer

26

3


27

4

Lock washer, M6 ribbed

28

4

SHCS M6- 1.0 x 35mm

29

3

Piston

Item

21

Qty.

Description

30

1

Pump head

31

3

Inlet check valve

32

3

Outlet check valve

33

1

Hex socket set screw w/ Locktite DO NOT REMOVE

34

1


35

1


36

1

Pop off valve ball seat

37

1

Pop off valve check ball

38

1

O-ring

39

4

Rubber mount

40

2

Taptite screw, M4-0.7x10mm

41

4

Plastite screw, 6-19 x 0.75”

42

1

Backup ring

43

1

O-ring

44

1


45

1

Auto switch piston return spring

46

1


47

1

Backup ring

48

1

Retainer cap

49

1

Auto switch grommet

50

1

Auto switch

51

1

Auto switch housing

52

1

Chemical suction hose

53

1

Hose clamp

54

1

Chemical inject fitting

55

1

Chemical inject check ball

56

1

Chemical inject check spring

57

1

Chemical inject venturi

58

1

Venturi o-ring


Part 2 - Disassembly

Figure 4.3 — Pump Head

General Information & Special Tools

NOTE: There are no special tools required to disassemble or reassemble this pump. CAUTION: The pump is full of oil. When removing pump from motor, drain by pouring oil out of crankcase. Pump Head Refer to Figure 4.3 for this procedure. Using a 5mm Allen wrench, remove the four (4) M6-1.0 x 35 cap screws to separate pump head from piston housing. To disassemble pump head: 1. Remove the three (3) high pressure water seals (item 2). Seals should slide out easily.

Item

Name

1

Inlet check valve assembly

2


3. Remove the o-ring (item 3) from the pop off valve boss.

3

Pop off o-ring

4. Secure the head in a vice or with a clamp and use an 8mm wrench to remove the three (3) M8-1.5 outlet port caps (items 5 & 6).

4

Outlet check valve assembly

5

Outlet port cap o-ring

6

Outlet port cap

7

Check valve o-ring

8


9

Pop off check ball

10

Hex socket plug DO NOT REMOVE

11


12

Pop off ball seat

13

M6 ribbed lock washer

14

SHCS, M6-1.0 x 35mm

15

Pump head

2. Remove the three (3) inlet check valves (item 1). A 5/16”-18 bottoming tap may be used to remove these valves.

5. Remove the three (3) outlet check valves and o-rings (items 4 & 7). 6. Do not attempt to remove the pipe plug (item 10) from the head (item 15). It is installed with a thread-locking compound to secure the pop off components and is not meant to be removed. Should these components be damaged or broken, the entire head assembly must be replaced.

22


WARNING: There may be up to 50 pounds of stored energy when separating the piston housing from the motor. Remove these bolts slowly and evenly.

Piston Housing Removal Refer to Figure 4.4 for this procedure. Figure 4.4 — Piston Housing

4. Using a 5mm wrench, gradually loosen each of the three (3) M6-1.0 x 20 bolts that hold the motor to the piston housing, as seen in Figure 4.5. Figure 4.5 — Motor Removal

Item

Name

1

Piston housing

2

Piston

3

Pilot spacer

4

Check valve o-ring

Item

Name

5

Shuttle valve o-ring

1

Electric motor

2

SHCS, M6-1.0 x 20mm

3

Piston housing

Before disassembling the piston assembly, do the following: 1. Remove the three (3) pilot spacers (item 3). These will just slide off.

NOTE: Piston housing is full of gear oil. Take care

2. Remove the three (3) check valve o-rings (item 4).

to handle the fluid safely.

3. Remove the shuttle valve o-ring (item 5).

23


Piston Housing Disassembly Refer to Figure 4.6 for this disassembly, as follows:

Chemical Injection System Not all pumps are equipped with a chemical injection system. Refer to Figure 4.7 when following this disassembly procedure.

Figure 4.6 — Piston Housing Disassembly

Be careful not to lose check ball and spring. Figure 4.7 — Chemical Inject System

Item

Name

1

Chemical inject venturi (brass or plastic)

2

Venturi o-ring

3


Item

Name

4

Check ball

1

Housing o-ring

5

Check spring

2


6

Piston housing

3

Piston

4

Piston spring

5

Piston housing

6

Oil seal

1. Remove the chemical injection fitting, check ball, and spring (items 3, 4, & 5). 2. Using a large straight tip screwdriver, unscrew and remove the chemical injection venturi and o-ring (items 1 & 2) from discharge port. It may be necessary to insert a sheet metal screw into the venturi hole, then pull on the screw with a pliers, to remove the venturi and o-ring.

1. Remove the large o-ring (item 1) from the housing. 2. Remove the three (3) pistons, springs, and retainers. To do this, grasp the piston springs and pull straight out. The retainers will stay attached to the pistons. 3. Remove the three (3) piston oil seals (item 6). 24


Auto Start Switch Assembly Refer to Figure 4.8 when following this disassembly procedure.

1. Remove the housing covering the auto switch (item 4) and disconnect two spade lugs from the switch. 2. Remove two (2) 5.5mm Taptite screws (item 3) using a 5.5mm socket. Remove the switch housing (item 4) from the piston housing.

Figure 4.8 — Auto Start Switch Group

3. Remove the retainer cap (item 11) with a 22mm socket or box wrench. Be careful to not round the hex head corners on this plastic part.

NOTE: The retainer cap, spring, and piston parts may show some slight differences depending on production date. Newer parts are completely interchangeable with older models. 4. Remove the piston spring and the piston components, as follows: a. To non-destructively remove the components, grasp the end of the piston shaft with a soft-jaw locking pliers and lever the assembly out of its port, prying against the port rim. b. If no soft-jaw pliers are available, a short length of brass tubing can be slipped over the piston shaft. A standard locking jaw plier can be used to grasp the tubing and squeeze it against the shaft, then remove as described in (a.). Item

Name

1

Piston housing

2

Rubber diaphragm

3

Taptite screw

4

Auto switch housing

5

Auto switch

6

Auto switch piston spring

7


8

O-ring

9


10

Backup ring

11

Retainer cap

12

O-ring

13

Backup ring

Any other removal method will require replacement of all auto switch piston components.

25


Axial Cam Refer to Figure 4.9 when following this disassembly procedure.

1. Grasp the protruding end of the axial cam idler shaft (item 1) with your fingers and withdraw it from the motor housing (item 5). 2. Remove the two thrust washers and the needle bearing.

Figure 4.9 — Axial Cam Components

3. Remove the axial cam/gear assembly. Because the gear is pressed onto the cam with special factory tooling, the cam and gear must be replaced as an assembly. 5. Remove the remaining thrust washers and needle bearing.

Item

Name

1


2

Bearing washer

3


4

Needle thrust bearing

5

Motor

6

Bearing washer

7

Bearing washer

8


26


Part 3 - Inspection

Each of the three (3) pump pistons pass through an oil seal in the piston and unloader housing. Note the oil seal and pilot spacer illustrated in Figure 4.11. The oil seal lip will face towards the piston spring and retainer to retain the pump oil.

Seals, O-Rings, and Gaskets Once the pump is disassembled, make a careful inspection of all seals and o-rings for any defects that may affect the proper operation of the pressure washer.

Figure 4.11 — Piston Seals

Piston & Spring Assemblies Referring to Figure 4.10, inspect the three (3) pistons carefully. Reject any piston that is scratched, dented, or otherwise damaged. Figure 4.10 — Piston & Spring Assemblies

Item

Name

1


2

Piston

3


Item

Name

1

Piston, spring, and retainer

2

Piston housing

3

Oil seal

4

Pilot spacer

5


Inspect the three (3) piston springs. Replace any spring that is damaged or broken. Pump Head and Piston Housing Clean all parts. Inspect carefully for cracks, damage, wear, etc.. Check for corrosion. Replace any damaged, defective, or corroded part as necessary.

WARNING: Do not strike a piston with any object or use a piston to strike any object.Do not drop the piston. Dropping the piston will result in damage.

27


Axial Cam Drive Components Referring to Figure 4.12, carefully inspect axial cam bearing assemblies for wear, damage, and freedom of rotation. Replace any damaged or defective bearing assembly.

Inspect the axial cam idler shaft. Replace if worn, bent, or damaged. Inspect the thrust washers. Replace if damaged. Inspect the axial cam/gear assembly. Replace if worn excessively or damaged. Inspect the motor assembly, particularly the axial cam housing. Ensure that the axial cam idler shaft socket is true and not worn or cracked. Ensure that the fastening bosses are not cracked or chipped. Inspect the housing for the absence of cracks, chips, evidence of oil leaks, or other damage.

Figure 4.12 — Axial Cam Components

Inspect the motor drive gear for evidence of wear or damage. Inspect the motor wires for evidence of corrosion, fraying or damaged connectors, wires, or other defects. Replace the motor assembly as a unit if any defects are found.

Item

Name

1


2

Bearing washer

3


4


5

Motor

6

Bearing washer

7

Bearing washer

8


28


Part 4 - Reassembly

found on Figure 4.2 (Exploded View) at the beginning of this chapter.

Refer to the Torque Specifications provided on the pump sectional view found at the beginning of this section when reassembling this product.

4. Press three (3) inlet check valves (item 1) into place. Notice that the small end of the valve goes into the cavity first, and that the valve is pressed in until it is flush with the head surface. It may be necessary to pre-lubricate the check valve o-rings with silicone spray before installation.

Pump Head Assembly The pop off valve is not serviceable. The entire head assembly must be replaced if a problem occurs in these components.

5. Pre-lubricate three (3) high pressure water seals (item 2) with silicone spray. Insert a seal into each piston cylinder cavity with the flat side facing out. Review Figure 4.11, seen earlier, for a view of proper seal orientation.

To assemble the pump head, refer to Figure 4.13 for the following steps:

6. Install the pop off valve o-ring (item 3). Petroleum jelly will help to hold it in place.

Figure 4.13 — Pump Head

Auto Start Switch Assembly Refer to Figure 4.14 for this assembly. Figure 4.14 — Auto Start Switch

Item

Name

1

Inlet check valve assembly

2


3

Pop off valve o-ring

4

Outlet check valve assembly

5


6

Outlet port cap

7

Check valve o-ring

8

Pump head

Item

Name

Item

Name

1

Piston housing

8

O-ring

2

Rubber diaphragm

9


3

Taptite screw

1. Install three (3) outlet check valve o-rings (item 7). Ensure they lie flat at the bottom of the cavity.

4

Auto switch housing

10

Backup ring

11

Retainer cap

2. Install three (3) outlet check valves, with large end first (item 4).

5

Auto switch

12

O-ring

6

Auto switch piston spring

13

Backup ring

7


3. Install and snug the three (3) M18-1.5 outlet caps with pre-installed o-rings (items 5 & 6). After the pump is assembled, tighten the three (3) outlet caps to the torque value specified in the Torque Chart, 29


Before assembly, ensure the auto switch cavity is clean and free from scale, corrosion, dirt, etc.

Chemical Inject Assembly Refer to Figure 4.15 for this assembly.

1. If necessary, install new backup rings and o-rings (items 8, 10, 12, 13) to the auto start piston return stop (item 7).

Figure 4.15 — Chemical Inject System

2. Remove and do not replace the teflon rings on the auto switch piston assembly. These rings should be removed for optimum auto switch operation. 3. Install the auto switch piston return spring (item 6) in the auto switch cavity on the piston housing. 4. Install the auto switch piston assembly, ensuring that it engages the spring inserted in step (3.). 5. Install the auto switch piston return stop (item 9) on the piston shaft so that the small backup ring faces out. 6. Install the retainer cap (item 11) over the piston shaft and hand thread it into the piston housing. 7. Tighten the retainer cap to the torque value specified in the Torque Chart, found on Figure 4.2 (Exploded View) at the beginning of this chapter. 8. Ensure that the rubber diaphragm (item 2) is not damaged or perforated, and is installed in the hole in the side of the auto switch housing. 9. Using a 5.5mm socket, install two (2) Taptite screws to secure the auto switch housing to the piston housing. Make sure the auto switch housing is anchored at the midpoint of its lateral adjustment. After the pressure washer is assembled, it may be necessary to adjust the position of the auto switch housing to ensure proper auto switch operation.

Item

Name

1

Chemical inject venturi (brass or plastic)

2

Venturi o-ring

3


4

Check ball

5

Check spring

6

Piston housing

1. Install the check ball into the chemical inject fitting, followed by the spring (with the small end of the spring towards the ball). 2. Install the chemical inject fitting into the piston housing. Be careful not to drop the ball and spring. 3. Tighten the chemical injection fitting to the torque value specified in the Torque Chart, found on Figure 4.2 (Exploded View) at the beginning of this chapter. 4. Carefully install the chemical inject venturi o-ring onto the venturi. 5. Hand thread the chemical inject venturi into the discharge port of the piston housing. 6. Tighten the venturi to the torque value specified in the Torque Chart, found on Figure 4.2 (Exploded View) at the beginning of this chapter. 30


Piston Housing Assembly Refer to Figure 4.16 for this procedure.

Pilot Spacer Installation Refer to Figure 4.17 for this procedure. 1. Install the three (3) check valve o-rings (item 4). Use a small amount of petroleum jelly to hold them in place.

Figure 4.16 — Pistons and Springs

Figure 4.17 — Piston Housing

Item

Name

1


2

Piston

Item

Name

3

Piston spring

1

Piston housing

4

Piston housing

2

Piston

5

Oil seal

3

Pilot spacer

4

Check valve o-ring

5

Shuttle valve o-ring

1. Pre-lubricate the three (3) oil seals (item 5) with silicone spray. Press the seals into the piston housing with their flat side (the side with writing on it) facing the installer. If you see the seal’s internal spring, the seal has been installed upside down.

2. Install the three (3) pilot spacers (item 3) over the pistons, with large end inserted in piston housing. 3. Install the shuttle valve o-ring (item 5). Use a small amount of petroleum jelly to hold it in place.

2. Apply a small amount of 80W90 oil to the three (3) pistons, then install the pistons, springs, and retainers into the piston housing. The pistons are merely pushed into place.

4. Carefully lift the pump head assembly, invert it, and align the high pressure water seals with the pistons protruding from the piston housing.

3. Invert the piston housing so that the pistons protrude vertically from the housing. Place the piston housing on a flat surface.

5. Verify that the o-rings remain in their proper position and press the head down to the piston housing. 31


Pump Head Bolts 1. Grasp the head/piston housing assembly and invert it onto a flat surface.

1. Invert the head/piston housing assembly and place it on a flat surface. Ensure that the pistons are fully inserted into the piston housing.

2. Install the four (4) M6-1.0 x 35 cap screws . Tighten the cap screws to the torque value specified in the Torque Chart, found on Figure 4.2 (Exploded View) at the beginning of this chapter.

2. Install the axial cam idler shaft (item 7) into its socket in the piston housing (item 8).

Assemble Axial Cam Refer to Figure 4.18 for this procedure:

4. Lay a 40 x 60mm needle bearing (item 5) on the thrust washer, either side up.

3. Install a 36 x 60 x 6mm thrust washer (item 6) on the idler shaft, with chamfer towards the pistons.

5. Lay a 40 x 60 x 1mm thrust washer (item 4) on the needle bearing, chamfer side up.

Figure 4.18 — Axial Cam Assembly

6. Install the axial cam/gear assembly (item 3) onto the idler shaft, gear end on top. Ensure that the axial cam engages the bearing and thrust washers previously installed. 7. Install a 35 x 55 x 3mm thrust washer (item 2) on the axial cam, with chamfer towards the cam. 8. Install a 35 x 52mm needle thrust bearing (item 1) on the thrust washer (either side up). 9. Install the large o-ring into the piston housing groove. 10. Ensure that the idler shaft protrudes from the axial cam/bearing assembly about 8mm. This will make motor alignment easier. Oil Fill Pour the specified amount of 80W90 oil into the piston housing. For specific recommendations for oil type and capacity, please refer to the table given in Part 1, at the beginning of this section. Main Component Assembly 1. Use a dab of petroleum jelly to adhere the remaining 35 x 55 x 3mm thrust washer in its recess in the motor housing, with chamfer towards the motor housing. Item

Name

1


2

Bearing washer

3


4

Bearing washer

5


6

Bearing washer

7


8

Pump head/piston housing assembly

2. Grasp the motor assembly with both hands and invert it over the piston housing so that the axial cam idler shaft aligns with the mating hole in the motor housing. Gently lower the motor and rotate the cam to ensure the gear teeth engage the motor drive gear teeth. 3. Align the mounting screw holes on the motor housing with the threaded holes on the piston housing.

32


CAUTION: The motor adapter bolt holes line up with the holes on the piston housing in one position only. Rotate the motor housing until proper alignment is achieved.

Final Assembly and Test

NOTE: Torque the outlet caps at this time, if not done previously. Verify that all other fasteners have been torqued to proper values.

4. Referring to Figure 4.19, install the three (3) M6-1.0 x 20 socket head cap screws into the mounting screw holes on the motor housing and thread them into the piston housing. Because of piston return spring tension, the motor housing will remain elevated.

1. Position the motor cover housing over the pump assembly, feeding the two white wires up through the channel in the housing, as show on Figure 4.1. 2. Insert the bayonet plug into its mating connector in the housing and switch assembly.

Figure 4.19 — Motor Assembly

3. Insert the spade connector into its mating spade lug in the housing and switch assembly. 4. Fasten the housing and switch assembly to the motor cover housing with four (4) Plastite 6-19 x 0.75” screws. 5. Reassemble the pump into the pressure washer housing, taking care to avoid pinching wires, etc. 6. Cthe pressure washer to a water supply and connect the high pressure hose, wand, and spray gun. Connect the pressure washer to line voltage through a GFCI receptacle. 7. The pressure washer should provide a spray when the spray gun trigger is depressed. If the unit does not produce a spray, the auto switch may need to be adjusted, as follows: a. Disconnect the pressure washer from line voltage and from the water supply. b. Disassemble the unit so that you can get to the two taptite screws.

Item

Name

1

Electric motor

2

SHCS, M6-1.0 x 20mm

3

Piston housing

c. Loosen the screws enough to be able to laterally move the auto switch housing further away from the piston housing. d. Tighten the taptite screws to recommended torque value. e. Reassemble the unit, reconnect the water and line voltage and depress the spray gun trigger again. Normal unit operation should be obtained.

5. Snug each M6-1.0 cap screw, alternating between screws until the housings meet. Tighten screws to the torque value specified in the Torque Chart, found on Figure 4.2 (Exploded View) at the beginning of this chapter.

33


Part 5 - Troubleshooting Problem

Possible Cause

Corrective Action

1. Water leakage between pump head and piston housing.

a. Head bolts improperly torqued.

a. Torque head bolts.

b. Damaged head.

b. Replace head.

c. Missing or damaged o-rings

c. Install new o-rings.

a. Connector not properly sealed.

a. Seal with teflon tape and tighten properly.

b. Damaged connector.

b. Replace bad connector.

a. Defective or missing motor adapter o-ring.

a. Install new o-ring.

b. Motor adapter cap screws not tightened properly.

b. Tighten to correct torque.

4. Oil leak between motor adapter and piston/unloader housing.

a. Missing or bad o-ring seal.

a. Install new o-ring seal.

b. Cap screws not tightened properly.


5. Pump does not produce pressure, exhibits erratic pressure, chatters, or has a low water volume.

a. Nozzle is set to low pressure mode.

a. Reset nozzle to high pressure.

b. Incorrect spray nozzle is used.

b. Replace with correct nozzle.

c. Spray nozzle is obstructed.

c. Clear obstruction from nozzle.

d. Water Inlet blocked

d. Clear inlet.

e. Inadequate water supply to pump.

e. Provide sufficient water supply.

f. Water supply hose kinked or leaking.

f. Relieve kinking or repair leak.

g. Clogged inlet hose strainer.

g. Clean strainer.

h. Water supply too hot.

h. Reduce inlet water temperature to below 140oF.

i. Worn or defective pump.

i.

a. Nozzle is in “high pressure” mode.

a. Reset nozzle to “low pressure”.

b. Chemical suction line is not submerged.

b. Insert line into fluid.

c. Chemical suction strainer or line is clogged.

c. Clean or replace strainer or line.

2. Water leaks from pressure out connector.

3. Oil leak between motor and motor adapter.

6. Detergent does not mix with spray.

34

Disassemble and repair pump.

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 5 • Small Frame Gas Pump

SMALL FRAME GAS PUMP This section describes the small frame pump assemblies powered by gasoline engines intended for use in light duty applications. This small frame gas pump may also be referred to as ‘GPW-EG’ or ‘EG’ or ‘Economy Gas’ pumps. Most of the information previously printed in publication A4453 will be found here. The small frame gas pump has the following features: • 1500 to 1800 PSI water pressure • 2.0 Gallons per minute flow • Axial Cam Design • Stainless Steel Pistons • Fixed Pressure Unloader • Chemical Injection System available • Thermal Relief Valve available • Oil Bath Drive System • Vertical or Horizontal Engine Mount

Part 1 - Specifications and Views This section presents the torque and performance specifications for Generac Portable Products® small frame gas pumps. Also presented are sectional and exploded views of this type of pump assembly. Performance Specifications Pump Assembly Part No.‡

Rated Pressure+

Engine Shaft

Pump Head

Flow Rate*

Piston Material

Oil Type/ Capacity

B1906A 20965 20965A B1262 B1262A

1500 1650 1650 1750 1750

Straight Straight Straight Straight Straight

Aluminum Aluminum Aluminum Aluminum Aluminum

2.0 2.0 2.0 2.0 2.0

Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel

80W90/120ml 80W90/120ml 80W90/120ml 80W90/120ml 80W90/120ml

+ Pressure (in pounds per square inch) is adjustable up to the unit's rated pressure. * Flow rate is given in gallons per minute. ‡ ‘A’ suffix denotes pumps with thermal relief valve. Pump assemblies are listed by part number and were current at time of publication. Other pump assemblies will become available as our products evolve.

35


Cross-Sectional view

A typical small frame gas pump is shown in cross-section in Figure 5.1.

Figure 5.1 — Small Frame Gas Pump (cross-sectional view)

36


Cross Sectional View Parts List Item

Qty.

Description

1

3

Rubber grommet spacer sleeve

2

1

3

Item

Qty.

Description

25

1

Unloader seat O-Ring

Cage needle bearing assembly

26

1

Unloader piston

1

Bearing washer

27

2

Unloader split-ring seal

4

1

Bearing washer

28

1

Unloader spring

5

3

Oil piston seal

29

1

Unloader cap O-Ring

6

3


30

1

Unloader cap

7

3

U-cup seal

31

1

8

1

Axial cam w/insert

Pipe plug (if item 22 not equipped) w/sealant

9

1

Engine adapter

32

1

Chemical injection hose barb

1

Plug, w/sealant

10

1

Piston and unloader housing

33

11

3


34

1

Chemical injection ball

12

3

Pilot spacer

35

1

Chemical injection spring

13

3

Piston

36

1


14

1

Pump head

37

6

Low pressure transfer O-Ring

15

1

Radial ball bearing

39

7

Lock washer

16

6

Rubber bushing

40

4

Socket head cap screw

17

1


M6-1.0 x 35

O-Ring seal 18

1

42

3

43

1

M6-1.0 x 25

High pressure transfer O-Ring

20

6

Check valve assembly

21

3

Outlet check valve cap O-Ring

22

1

Thermal relief valve (if equipped) w/sealant

23

3

Outlet check valve cap

24

1

Unloader seat


37

Venturi O-Ring


Exploded View

A typical small frame gas pump is shown in exploded view in FIgure 5.2.

Figure 5.2 — Small Frame Gas Pump (exploded view)

Torque Chart Torque Item 23

15-17 ft-lbs

30

Brass: 15-18 ft-lbs Plastic: 7-10 ft-lbs

38

31

15-18 ft-lbs

32

9-12 in-lbs

33

12-15 ft-lbs

36

20-30 in-lbs

40

9-12 ft-lbs

42

9-12 ft-lbs

43

15-18 ft-lbs



Qty.

Description

1

3

Rubber grommet spacer sleeve

2

1

3

Qty.

Description

26

1

Unloader piston

Cage needle bearing assembly

27

2

Unloader split-ring seal

1

Bearing washer

28

1

Unloader spring

4

1

Bearing washer

29

1

Unloader cap O-Ring

5

3

Oil piston seal

30

1

Unloader cap

6

3


31

1

7

3

U-cup seal

Pipe plug (if item 43 not equipped) w/sealant

8

1

Axial cam w/insert

32

1

Chemical injection hose barb

9

1

Engine adapter

33

1

Plug, w/sealant

10

1


34

1


11

3


35

1


12

3

Pilot spacer

36

1


13

3

Piston

37

6


14

1

Pump head

39

7

Lock washer

15

1

Radial ball bearing

40

4


16

6

Rubber bushing 42

3

17

1

Item

M6-1.0 x 35


M6-1.0 x 25

O-Ring seal 18

1


20

6

Check valve assembly

21

3


23

3


24

1

Unloader seat

25

1

Unloader seat O-Ring


43

1

Thermal relief valve (if equipped) w/sealant

45

39

1

Venturi O-Ring



To disassemble pump head:


1. Remove the three (3) water seals. Seals should slide out by hand.

NOTE: There are no special tools required to disassemble or reassemble this pump.

2. Remove the three (3) inlet check valves. A 5/16”-18 bottoming tap may be used to remove these valves. DO NOT use a screwdriver as it will damage valve and head!

CAUTION: The pump is full of oil. When removing pump from engine, drain by pouring oil out of port used by the crankshaft.

3. Remove the O-Ring from the high pressure transfer boss. 4. Remove the three (3) M8-1.5 outlet check valve caps and O-Rings.

Pump Head Refer to Figure 5.3 for this procedure.

5. Remove the three (3) outlet check valves and O-Rings. 6. Do not attempt to remove the pipe plug (item 7). It is installed with a thread-locking compound and is not meant to be removed.

Figure 5.3 - Pump Head

Piston & Unloader Housing Removal Refer to Figure 5.4 for this procedure. Figure 5.4 - Pump-Adapter Assembly

Item

Name

1

Water seal

2

Check valve

3


4


5


6


7

Item

Name

1

Piston

Pipe Plug - If present, DO NOT REMOVE

2

Pilot spacer

8

M6 lock washer

3


9

M6-1.0 x 35 cap screw

Before disassembling the piston and unloader assembly, do the following:

Using a 5mm Allen wrench, remove the four (4) M6-1.0 x 35 cap screws and lockwashers to separate pump head from piston housing.

1. Remove the three (3) pilot spacers. These will just slide off. 40


Piston & Unloader Housing Disassembly Refer to Figure 5.6 for this disassembly, as follows:

2. Remove the three (3) low pressure transfer O-Rings.

WARNING: There may be up to 75 pounds of stored energy when separating the piston and unloader housing from the engine adapter housing. Remove these bolts slowly and evenly.

Figure 5.6 - Piston & Unloader Housing

3. Apply a 6” C-clamp to hold the engine adapter and the pump head together. 4. Remove the three (3) M6-1.0 x 25 cap screws that hold the engine adapter to the piston and unloader housing, as seen in Figure 5.5. Figure 5.5 - Engine Adapter

Item

Name

1

M6-1.0 x 25 cap screw & M6 lock washer

2

Engine adapter

Item

Name

1

O-Ring

2

Piston and retainer

3

Spring

4

Thermal bypass valve or pipe plug

5


6

Piston oil seal

1. Remove O-Ring from housing.

5. Slowly loosen the C-clamp until spring tension is released and the components separate.

2. Remove the three (3) pistons, springs, and retainers. To do this, grasp the piston springs and pull straight out. The retainers will stay attached to the pistons. 3. Remove the three (3) piston oil seals. 4. Remove the thermal relief valve (if present). It is not necessary to remove the pipe plug, if installed in place of the thermal relief valve.

41


Chemical Injection System Refer to Figure 5.7 and follow this chemical injection system disassembly procedure.

Unloader Refer to Figure 5.8 when following this disassembly procedure.

CAUTION: Unloader cap is under strong spring

Figure 5.7 - Chemical Injection System

pressure. 1. Remove the M25-1.0 unloader cap with a 24mm wrench.

NOTE: Unloader cap, unloader spring, and unloader piston parts may show some slight differences depending on production date. If the entire unloader system is replaced, newer assemblies are completely interchangeable with older models. Figure 5.8 - Unloader Parts

Item

Name

1


2

O-Ring

3

Barbed nipple

4

Check ball

5

Spring

6


Item

Name

1


2

O-Ring

3

Unloader seat

CAUTION: Be careful not to lose check ball and

4

Unloader piston

spring.

5

Unloader cap

6

Unloader spring

7

Split-ring seal

1. Remove the chemical injection fitting, check ball, and spring. 2. Using a large straight tip screwdriver, unscrew and remove the chemical injection venturi and O-Ring from discharge port.

2. Remove the unloader spring and the unloader piston. These pieces should just slide out. 3. Remove the unloader seat by inserting a 90° O-Ring pick into the orifice machined in the side of the seat, then gently pull the seat out of the housing.

42


Part 3 - Inspection

Engine Adapter Refer to Figure 5.9 when following this disassembly procedure.

Seals, O-Rings, and Gaskets Once the pump is disassembled, make a careful inspection of all seals and O-Rings for any defects that may affect the proper operation of the pressure washer.

Figure 5.9 - Engine Adapter & Axial Cam

Piston & Spring Assemblies Referring to Figure 5.10, inspect the three (3) pistons carefully. Reject any piston that is scratched, dented, or otherwise damaged. Figure 5.10 - Piston Assembly

Item

Name

Name

1

Retainer

1

Thrust washer

2

Piston

2

Cage needle bearing

3

Spring

3

Retainer washer

4

Axial cam

5

Radial ball bearing

6

Engine adapter

Item

CAUTION: Do not strike a piston with any object or use a piston to strike any object.Do not drop the piston. Dropping the piston will result in damage.

1. Remove the thrust washer. 2. Remove the cage needle bearing. 3. Remove the retainer washer. 4. Remove the axial cam/radial ball bearing assembly. Because the bearing is pressed onto the cam, the cam and bearing must be replaced as an assembly. 5. If present, the pipe plug was installed with a threadlocking compound and should not be removed.

43


Axial Cam Drive Components Referring to Figure 5.12, carefully inspect the engine adapter bearing and the axial cam bearing assemblies for wear, damage, and freedom of rotation. Replace any damaged or defective bearing assembly.

Each of the three (3) pump pistons pass through an oil seal in the piston and unloader housing. Note the oil seal and pilot spacer illustrated in Figure 5.11. The oil seal lip will face towards the piston spring and retainer to retain the pump oil.

Figure 5.12 - Axial Cam Drive Components

Figure 5.11 — Piston Chamber

Item

Name

1


2

Piston

3

Oil seal

4

Pilot spacer

5

Pump head

Inspect the three (3) piston springs. Replace any spring that is damaged or broken. Engine Adapter, Pump Head, and Piston & Unloader Housing Clean all parts. Inspect carefully for cracks, damage, and so forth. Check for corrosion. Replace any damaged, defective, or corroded part as necessary.

Item

Name

1

Thrust washer

2

Cage needle bearing

3

Retainer washer

4

Axial cam

5

Radial ball bearing

6

Engine adapter

Inspect the retainer washer and the thrust washer. Replace if damaged. Inspect the axial cam. Replace if worn excessively or damaged.

44


Part 4 - Reassembly

4. Install the unloader piston. It will seat itself inside of the unloader seat.

NOTE: Refer to the Torque Specifications provided

5. Install the unloader spring.

on the pump exploded view found at the beginning of this section when reassembling this product.

6. Install the M25-1.0 unloader cap and O-Ring. 7. Tighten the unloader cap to the torque value specified in the Torque Chart, found on Figure 5.2 (Exploded View) at the beginning of this chapter.

Engine Adapter 1. Install the retainer washer (thinner one) on the axial cam/radial ball bearing assembly.

Chemical Injection Assembly Refer to Figure 5.14 for this assembly.

2. Install the cage needle bearing (either side up). 3. Install the thrust washer (thicker one, either side up).

Figure 5.14 - Chemical Injection System

Unloader Assembly Refer to Figure 5.13 for this assembly. Figure 5.13 - Unloader Assembly

Item

Name

1


2

O-Ring

3

Unloader seat

4

Unloader piston

5

Unloader cap

6

Unloader spring

7

Split-ring seals

Item Name 1


2

O-Ring

3

Barbed nipple

4

Check ball

5

Spring

6


1. Install the check ball into the chemical injection nipple, followed by the spring (with the small end of the spring towards the ball).

1. Install the new O-Ring on the unloader seat (if replacing). 2. Install the unloader seat with O-Ring (use a small amount of petroleum jelly on O-Ring if necessary). Seat will press itself into place when unloader piston, spring, and cap are installed.

2. Install the M10-1.0 chemical injection nipple into the piston and unloader housing. Be careful to not drop the ball and spring.

3. Install the new split-ring seal onto the unloader piston (if replacing).

3. Tighten the chemical injection nipple to the torque value specified in the Torque Chart, found on Figure 5.2 (Exploded View). 45


2. Apply a small amount of 80W90 oil to the three (3) pistons, then install the pistons, springs, and retainers into the piston and unloader housing. The pistons are merely pushed into place.

4. Install the chemical injection venturi O-Ring into the piston and unloader housing. 5. Hand thread the M14-1.25 chemical injection venturi into the housing.

3. Install the thermal relief valve (item 3).

6. Tighten the venturi to the torque value specified in the Torque Chart, found on Figure 5.2 (Exploded View).

4. Tighten the thermal relief valve (or substitute plug) to the torque value specified in the Torque Chart, found on Figure 5.2 (Exploded View) at the beginning of this chapter.

Piston & Unloader Housing Assembly Refer to Figure 5.15 for this assembly.

Pump Head Assembly Refer to Figure 5.16 for this assembly.

Figure 5.15 - Piston & Unloader Housing


Item

Name

1

O-Ring

2

Piston and retainer

3

Spring

4

Thermal bypass valve or pipe plug

5


6

Piston oil seal

1. Refer to Figure 5.15 and install the three (3) oil seals. Press the seals into the piston and unloader housing using a small amount of petroleum jelly.

Item

Name

1

Water seal

2

Check valve

3


4


5


6


7

Pipe Plug - If present, DO NOT REMOVE

8

M6 lock washer

9


1. Install the three (3) low pressure transfer O-Rings. Use a small amount of petroleum jelly to hold them in place.

NOTE: Do not reuse springs color coded RED. All piston return springs must be replaced in sets of three (3).

2. Install the high pressure transfer O-Ring. Petroleum jelly will help to hold it in place. 46


3. Press three (3) inlet check valves into place, as shown in Figure 5.16.

3. Place the piston housing O-Ring into the groove on the housing.

4. Install three (3) outlet check valves, observing their orientation, as shown in Figure 5.16.

4. Grasp the engine adapter with both hands and invert it while holding the axial cam, washers, and bearing in place.

5. Install the three (3) M18-1.5 outlet caps and O-Rings.

5. Place the engine adapter over the piston housing so that the thrust bearing is touching all three (3) pistons, and the mounting screw holes on the adapter line up with the threaded holes on the housing.

6. After the head is bolted to the pump, tighten the three (3) outlet caps to the torque value specified in the Torque Chart, found on Figure 5.2 (Exploded View) at the beginning of this chapter.

6. Referring to Figure 5.18, install the three (3) M6-1.0 x 25 socket head cap screws into the mounting screw holes on the engine adapter and thread them into the piston housing.

Main Component Assembly Refer to Figure 5.17 for this assembly.

Figure 5.18 — Installing Engine Adapter Bolts

Figure 5.17 — Main Component Assembly

Item Name

Item

Name

1

Engine adapter assembly with axial cam, bearings, and washers held in place.

2

Assembled piston and unloader housing with pistons, seals, and O-Ring

3

Pump head assembly placed on flat surface

1

M6-1.0 x 25 cap screws & M6 lock washers

2

Engine adapter

3

Widest opening between three (3) engine adapter ‘legs’ aligns with the chemical injector-thermal relief side of piston and unloader housing

4

Pump head

7. Tighten the M6-1.0 cap screws to the torque value specified in the Torque Chart, found on Figure 5.2 (Exploded View) at the beginning of this chapter.

NOTE: The engine adapter bolt holes line up with the holes on the piston housing in one position only. Use the widest of the three openings between the engine adapter ‘legs’ as a reference. This opening should line up roughly with the chemical injection/thermal relief valve side of the piston housing.

1. Place the pump head assembly on a flat surface, with the inner side up. 2. Position the piston and unloader housing on the pump head so that the pistons line up with their respective cylinders in the pump head. 47


Pilot Spacer Installation 1. Grasp the complete pump assembly with both hands and turn it over onto the three (3) engine adapter ‘legs’, as shown in Figure 5.19.

3. Install the three (3) low pressure transfer O-Rings around the inlet openings on the piston housing, as seen in Figure 5.20. Figure 5.20 — Install Pilot Spacers/O-Rings

Figure 5.19 — Invert Pump Assembly

2. Carefully lift the pump head from the pump and slide the three (3) pilot spacers over the pistons, which will be protruding from the piston housing.

48

Item

Name

1

Pump head

2

Pilot spacer

3


4

Piston


Pump Head Bolts Referring to Figure 5.21, reposition the pump head and install the four (4) M6-1.0 x 35 cap screws.

Oil Fill As shown in Figure 5.22, set the pump on its head. Pour in the specified amount of 80W90 oil through the port used by the engine crankshaft.

Figure 5.21 — Head Bolt Installation

Item

Name

1


2

M6 lock washer

3

Piston & unloader housing attached to engine adapter

Figure 5.22 — Oil Fill

Verify that the oil level reaches the upper lip of the piston housing, as shown in Figure 5.23. The pump can now be installed onto the engine. Figure 5.23 — Oil Level

Tighten the M6-1.0 cap screws to the torque value specified in the Torque Chart, found on Figure 5.2 (Exploded View) at the beginning of this chapter.

NOTE: Torque the outlet check valve caps at this time, if not done previously.

For specific recommendations for oil type and capacity, please refer to the table given in Part 1, at the beginning of this section.

49



Possible Cause

Corrective Action

1. Water leakage between pump head and piston housing.



b. Damaged head.

b. Replace head.



a. Connector not properly sealed.




a. Defective or missing motor adapter o-ring.

a. Install new o-ring.

b. Motor adapter cap screws not tightened properly.


4. Oil leak between motor adapter and piston/unloader housing.





5. Pump does not produce pressure, exhibits erratic pressure, chatters, or has a low water volume.

a. Nozzle is set to low pressure mode.

a. Reset nozzle to high pressure.

b. Incorrect spray nozzle is used.

b. Replace with correct nozzle.

c. Spray nozzle is obstructed.

c. Clear obstruction from nozzle.


d. Clear inlet.






g. Clean strainer.




i.







2. Water leaks from pressure out connector.

3. Oil leak between motor and motor adapter.


50


Portable Pressure Washer Familiarization and Troubleshooting Guide Section 6 • Medium Frame Pump

MEDIUM FRAME PUMP This section describes the medium frame pump assemblies powered by gasoline engines. This medium frame pump may also be referred to as ‘GPW-FH’ or ‘flat head’ pumps. The medium frame pump has the following features: • 1800 to 2250 PSI water pressure • 2.0 to 2.5 Gallons per minute flow • Axial Cam Design • Ceramic Pistons • Easy Start Unloader • Adjustable Output Water Pressure • Chemical Injection System available • Thermal Bypass Valve available • Oil Bath Drive System • Vertical and Horizontal Engine Mount

Part 1 - Specifications and Views This section presents the performance specifications for Generac Portable Products® medium frame pumps. Also presented are sectional and exploded views of this type of pump assembly. A table listing torque specifications may be found on the exploded view page. Pump Assembly Part No.‡

Rated Pressure+

Flow Rate*

Unit Style

Engine Shaft

Pump Head

Piston Material

Oil Type/ Capacity

A1803 A1803A A1803C A1803C B3166 B3166A B3166C B3166C B3358 B3358 B3358A B3358C B3358D

2250 2000 2200 2200 2250 2000 2000 2000 2250 2250 2000 2200 2000

2.222 2.0 2.2 2.2 2.222 2.0 2.2 2.2 2.222 2.5 2.0 2.2 2.2

Horizontal Vertical Vertical Horizontal Horizontal Vertical Vertical Horizontal Vertical Horizontal Vertical Vertical Horizontal

Straight Straight Straight Straight Straight Straight Straight Straight Straight Straight Straight Straight Straight

Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum

Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic

80w90 280ml 80w90 305ml 80w90 305ml 80w90 280ml 80w90 280ml 80w90 305ml 80w90 305ml 80w90 280ml 80w90 305ml 80w90 280ml 80w90 305ml 80w90 305ml 80w90 280ml

Performance Specifications ‡ Pump assemblies are listed by part number and were current at time of publication. Other pump assemblies will be added as our product line evolves. + Rated Pressure is given in pounds per square inch. * Flow Rate is given in gallons per minute.

51



A typical medium frame pump is shown in cross section in Figure 6.1.

Figure 6.1 — Medium Frame Pump (cross-sectional view)

52


Sectional View Parts List Item

Qty

Description

1

3

Outlet port cap

2

3

3

Item 28

Qty 1

Description Oil breather cap

29

-

Loctite

O-ring, outlet port

30

1

O-ring

6

Check valve

31

1

Axial cam bearing assembly

4

3

O-ring, check valve

32

1

Axial cam

5

1

Head sub-assembly

33

1

Engine adapter

6

3

Bearing ring

34

1

Engine adapter bearing

7

3

High pressure seal

35

1

Thrust washer

8

3

O-ring, check valve

36

1

O-ring

9

1

Thermal bypass actuator and stem

37

1

Washer retainer

10

1

Trapped line pressure seat

38

1

Engine shaft adapter

11

1


39

1

C-ring cam retainer

12

1


40

4

Button head cap screw, 5/16”-24

13

1


or 4

Socket head cap screw, 5/16”-24

14

1


4

O-ring, if button head

15

1

Unloader ball spring

or 4

Flat washer, if socket head

16

1

Trapped line pressure piston assembly

43

3

Piston pivot shoe

17

1

Unloader ball

44

6

Socket head cap screw, M6-1.0

18

1

Ball seat assembly

45

3


19

1


46

1

Pump crankcase

20

1

Unloader handle

47

1

Spacer plate

21

1

Setscrew, M6-1.0 x 8mm

48

3

Pilot ring

22

1

Plastic cap

49

1

Head gasket

23

1

Unloader spring

50

6


24

1

Thermal actuator piston o-ring

51

6

Special steel washer

25

1

Thermal actuator spring

26

1

Thermal actuator piston

27

3

Piston

41

53


Exploded View

A typical medium frame pump shown in exploded view in Figure 6.2.

Figure 6.2 — Medium Frame Pump (exploded view)

Item

Torque Value

1

20-30 ft-lbs

11

10-12 ft-lbs

14

9-12 ft-lbs

19

20-23 ft-lbs

29

24-36 in-lbs w/Loctite

40

18-20 ft-lbs

44

10-12 ft-lbs

50

18-20 ft-lbs

Certain components have been changed, added, or deleted since this Medium Frame pump became available. Always refer to the Owner’s Manual shipped with each model pressure washer for appropriate part number references.

54


Exploded View Parts List Qty

Description

25

1

Thermal actuator spring

O-ring, outlet port

26

1

Thermal actuator piston

6

Check valve

27

3

Piston

4

3

O-ring, check valve

29

1

Oil breather cap

5

1

Head sub-assembly

30

1

O-ring

6

3

Bearing ring

31

1


7

3

High pressure seal

32

1

Axial cam assembly

8

3

Check valve

33

1

Engine adapter

9

1


34

1


10

1


36

1

O-ring

11

1

Chemical injection venturi assembly

40

4

Button head cap screw, 5/16”-24

12

1


or 4


13

1


41

4

O-ring, if button head

14

1


or 4

Flat washer, if socket head

15

1

Unloader ball spring

43

3

Piston pivot shoe

16

1


44

6


45

3


17

1

Unloader ball

46

1

Pump crankcase assembly

18

1

Ball seat assembly

47

1

Spacer plate assembly

19

1


48

3

Pilot ring

20

1

Unloader handle

49

1

Head gasket

21

1


50

6


22

1

Plastic cap

51

6

Steel washer

23

1

Unloader spring

24

1

Thermal actuator piston o-ring

Item

Qty

Description

1

3

Outlet port cap

2

3

3

Item

55



1. Referring to Figure 6.3, replace the two (2) M6-1.0 x 20 cap screws (identified with arrows on the figure) with two (2) M6-1.0x 45 hex head bolts.


2. Ensure the two bolts described in (1.) above are tight, then remove the four (4) remaining M6-1.0 x 20 cap screws.

DANGER:The pump removal procedures described in this section must be followed carefully or personal injury could result. During removal of the pump, very powerful springs tend to separate the pump crankcase from the engine adapter. Failure to follow the described procedure may result in a forceful separation of the components.

CAUTION: Do Not attempt to disassemble the pump without installing two longer screws to relieve the spring tension. 3. As indicated in Figure 6.4, start backing out the two bolts installed in (1.). Alternate between the two bolts, using them as a “jacking” device to separate the pump crankcase from the engine adapter while relieving spring tension from between these two components.

Differences may exist in pump head components. For example, the axial cam used on a pump rated 2.0 gallons per minute must necessarily be different than the axial cam used on a pump rated at 2.5 gallons per minute. Special tools needed: • Dead blow hammer

Figure 6.4 - Head Screw Removal

• 5/16”-18 bottoming tap • Brass rod, 5mm diameter x 20cm long Pump Head Before removing the pump head, disconnect the inlet water hose from the pump’s water inlet. Disconnect the spray gun high pressure hose from the pump’s high pressure outlet connector. Disconnect the chemical injection siphon tube from the chemical injection hose barb. Place a shallow pan underneath the pump crankcase to catch pump oil. Remove the pump, as described below: Figure 6.3 - Pump Head

4. As the pump crankcase is separated from the engine adapter, a piston pivot shoe (shown in Figure 6.5) Figure 6.5 - Pivot Shoe may fall out. Ensure that each shoe is identified with the same identification number as the piston it fell away from. Retain each shoe with its piston as a set for later inspection and installation.

56


Axial Cam Drive Components To disassemble medium frame units, refer to Figure 6.6 and proceed as follows:

Pistons and Piston Springs Refer to Figure 6.7 for this disassembly. The three (3) pistons along with their springs can be removed from the pump crankcase by grasping the springs and pulling straight out.

Figure 6.6 - Axial Cam Drive Components

Figure 6.7 - Piston Assembly

Item

Name

1

O-ring

2

Engine adapter

3


4

Axial cam assembly

5

Roller thrust bearing assembly

6

Button head cap screw

7

O-ring

1. Remove the pump piston bearing assembly (item 5) as a unit. 2. Remove the axial cam with pressed-in engine shaft adapter, thrust washer and retainers (item 4). 3. Remove the engine adapter bearing assembly (item 3). You may need to use a 90° o-ring pick to pull the bearing race out of the engine adapter housing. 4. Remove the four (4) 5/16”-24 screws that retain the engine adapter to the engine. The engine adapter can now be removed. 5. On units so equipped, completely remove the engine adapter gasket. If necessary, remove the pilot sleeve from these older-style engine adapters. This sleeve is secured into the housing with LockTite®.

57

Item

Name

1

Spring

2

Piston


Pump Head To remove the pump head assembly, refer to Figure 6.8 and proceed as follows:

Spacer Plate Referring to Figure 6.9, remove the spacer plate from between the crankcase and pump head, as follows:

Figure 6.8 — Pump Head Removal

Figure 6.9 - Spacer Plate Removal

Item

Name

Item

Name

1

Pump crankcase assembly

1

Spacer plate assembly

2

Pilot spacer

2

Head gasket

3

Spacer plate

3


4


4


5


5

Chemical injection check ball

6


7

Pump head assembly

8

Steel washer

9


1. Separate the spacer plate from the crankcase, being careful to not damage the thermal bypass spring and piston. 2. Remove the thermal bypass piston and the thermal bypass spring. 3. Remove the three (3) low-pressure water seals from the spacer plate.

1. Remove six (6) M8-1.25 socket head cap screws and M8 washers.

4. Completely remove all traces of the head gasket from the mating surface.

2. Remove the pump head assembly.

5. Remove the three (3) white pilot spacers from the pump crankcase.

3. Remove the thermal actuator stem. 4. Remove the three (3) check valve o-rings.

6. Using a small flat-blade screwdriver, gently remove the three (3) piston oil seals from the pump crankcase.

5. Gently remove the three (3) high pressure seals with a small flat-blade screwdriver. 6. Remove the three (3) plastic bearing rings. 7. Remove the head gasket and any remaining gasket material from mating surfaces. 58


Inlet Check Valves The three (3) inlet check valves are removed from the pump head with a standard 5/16”-18 bottoming tap.

3. Use a 90° o-ring pick to remove the o-ring from the base of the cavity. 4. Repeat steps 2 and 3 for the remaining outlet check valves.

1. As shown in Figure 6.10, gently turn the tap into the check valve with your fingers, approximately three full turns.

Unloader Spindle Assembly Referring to Figure 6.11: 1. Unscrew and remove the unloader handle, turning it counterclockwise.

Figure 6.10 - Inlet Check Valve Removal

Figure 6.11 - Unloader/Regulator and Chemical Inject Removal

Item

Name

1


2

Unloader handle

Item

Name

3


1

Outlet port cap

4

Spring

2


5


3

Outlet check valve

6

Check ball

4

O-ring

7


5

Pump head with tap threaded into inlet check valve

8

Trapped line pressure spring

9


10

Trapped line pressure piston

11

Unloader ball

12

Ball seat assembly

13

Pump head

14

Unloader spring

15

Plastic cap

2. When securely threaded, gently rock the check valve and withdraw it from its cavity.

CAUTION: Do not turn the tap in too far. An engagement of 2 or 3 threads is sufficient. Outlet Check Valves Referring to Figure 6.10: 1. Remove the outlet port cap.

3. Carefully loosen and unscrew the unloader spindle assembly with a 19mm deep socket or wrench.

2. Grasp the end of an outlet check valve with a needle nose plier and pull it out. 59


Chemical Injection System Refer again to Figure 6.11 and follow this procedure to disassemble the rest of the unloader mechanism and the chemical injection system:

Thermal Bypass Actuator Removal 1. Referring to Figure 6.12, secure the pump head to a rigid surface, taking care to not damage the milled surfaces. Figure 6.12 — Thermal Bypass Actuator Removal

CAUTION: Be careful not to lose check ball and spring. 1. Remove the chemical injection fitting, check ball, and spring. 2. Using a large straight tip screwdriver, unscrew and remove the chemical injection venturi and o-ring from discharge port. Be careful not to strip the venturi slot. It may be necessary to use a sheet metal screw inserted in the center hole of the venturi. Grab the screw with pliers and pull to remove the venturi. 3. Insert a 0.25” diameter, 8” long brass rod through the unloader spindle opening. Push out the trapped line pressure seat, the 9/32” ball, and the rest of the unloader components. It may be necessary to gently tap the end of the rod with the dead blow hammer.

Item

Name

1

Flat blade screw driver

2

Thermal actuator

2. Insert a medium-sized flat-blade screwdriver in the pump head water passage so that its tip engages the lower lip of the thermal actuator. 3. Pry down on the screwdriver with a constant force, taking care to avoid severely gouging the head surface under the screwdriver. 4. The thermal bypass actuator will slide up and out of the pump head.

60


Part 3 - Inspection

Check Valves The check valves used in the pump illustrated in this chapter are the same for the inlet and outlet, as shown in Figure 6.14.

Seals, O-Rings, and Gaskets Replace seals and gaskets during the reassembly process. Seals Each of the three (3) pump pistons pass through seals in the pump crankcase, spacer plate, and head. Figure 6.13 shows the orientation of each of these seals.

Figure 6.14 — Typical Check Valve

Figure 6.13 — Piston Seals

Earlier pump models used inlet check valves different from outlet check valves. Be sure to observe the type of valve as they are removed so that proper reassembly can be performed. Item

Name

1

Pump head

2

Bearing ring

3

High pressure seal

4

Spacer plate

5

Low pressure seal

6

Pilot spacer

7

Oil seal

8

Crankcase

9

Piston

Replacement check valves and o-rings are provided in the seal kit. Head Gasket The head gasket is installed between the pump head and the spacer plate. Different versions have been used (two are seen in Figure 6.15), but the current gasket will replace all previous gaskets. Replace the gasket each time the pump is reassembled. Figure 6.15 — Two Types of Head Gaskets

The oil seal in the pump crankcase is oriented with the groove towards the crankcase. If you see the internal spring when installed, the seal is installed backward. The high-pressure seal in the pump head is oriented with the flat surface and writing visible. If you see the grooved surface when installed, the seal is pressed in backwards. Remember that the bearing ring is installed in the head before the seal is pressed in.

61


Engine Adapter O-Rings Examine the engine adapter o-ring and bolt head o-rings to ensure they are not damaged. Replace the engine adapter gasket each time the unit is reassembled. Newer gaskets can replace older gaskets.

Piston & Spring Assemblies Referring to Figure 6.7 (seen earlier), inspect the three (3) pistons carefully. Reject all three pistons if any one piston is scratched, dented, chipped, or otherwise damaged.

WARNING: Do not strike a piston with any object or use a piston to strike any object. Do not drop the piston.

Engine Adapter, Pump Crankcase, Spacer Plate and Head Clean all parts. Inspect carefully for cracks, damage, or other defects. Check for corrosion. Replace any damaged, defective, or corroded part as necessary.

Measure the piston diameter and the piston length (as shown in Figure 6.17). If the values are not within the tolerances specified below, replace all three pistons as a set:

Axial Cam Drive Components Referring to Figure 6.16, carefully inspect the engine adapter bearing and the axial cam bearing assemblies for wear, damage, freedom of rotation, or evidence of overheating. Replace any damaged or defective bearing assembly.

Figure 6.17 — Piston Dimensions

Figure 6.16 — Axial Cam Drive Assembly

Piston diameter: 14.977 mm to 14.985 mm Piston length: 86.65 mm to 90.05 mm Inspect the piston pivot shoes, depicted in Figure 6.18. If damaged, worn, scored, etc., you must replace all three (3) pistons and shoes as a set. Figure 6.18 — Piston Pivot Shoe

Item

Name

1

Engine adapter

2


3

Axial cam assembly

4


Inspect the axial cam assembly and the integral engine shaft adapter, which mates with an engine shaft keyway. This item is factory assembled must be replaced as a unit if the keyway or cam unit is worn or damaged.

62


High Pressure Outlet/Chemical Injection Assembly Referring to Figure 6.20, inspect the chemical injection and unloader components for signs of damage, obstructions, or wear. Replace any damaged or defective parts as necessary.

Inspect the three (3) piston springs. Ends must be closed and ground square. Check spring free length and load length as follows, referring to Figure 6.19: Figure 6.19 — Piston Return Spring

Figure 6.20 — High Pressure Outlet/Chemical Inject Assembly

Item

Name

1

Free length

2

Load length

1. Free length should be 62.57 mm (2.463”). 2. Apply a force of 51.0 to 56.4 pounds (227.2 to 251.1 Newtons). 3. At the stated load, spring length should be 39.8 mm (1.567”). 4. Replace all three (3) springs as a set if any one spring is damaged or broken. Replace the springs as a set if the free length or load length of any one spring does not meet specifications.

63

Item

Name

1


2

Unloader handle

3


4


5


6

Check ball

7


8

Spring

9

Venturi assembly

10


11

Unloader ball

12

Ball seat assembly

13

Head

14

Unloader spring

15

Plastic cap


Part 4 - Reassembly

Figure 6.22 — Engine Adapter Components

Refer to the Torque Specifications provided on the pump exploded view found at the beginning of this section when reassembling this pump. Engine Adapter 1. Early medium frame pumps may have an engine adapter pilot sleeve. Referring to Figure 6.21, apply LOCTITE Permabond No. HM160 to the outside of the larger diameter of the sleeve, then install the sleeve into the engine adapter as follows: Figure 6.21 — Engine Adapter Sleeve

Item

Name

1

Apply Loctite around the larger circumference of the ring in this area.

Item

Name

1

O-ring

2

Engine adapter

3


4

Axial cam assembly

5


6


7

O-ring

3. Retain the engine adapter to the engine with four (4) 5/16”-24x 3/4” screws and four (4) o-rings or washers.

CAUTION: When installing the engine adapter having the O-Ring seals, be sure to use the correct button head cap screws. DO NOT use any other type fastener.

a. From the inside of the engine adapter, press the smaller-diameter end of the adapter sleeve into the large bore of the engine adapter.

4. Tighten the screws to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View) at the beginning of this chapter.

b. Tap the adapter sleeve into the engine adapter bore until it seats flush against the inside machined surface of the engine adapter.

5. Install the engine shaft adapter over the engine shaft, ensuring the key in the axial cam adapter engages the keyway on the engine shaft.

2. Referring to Figure 6.22, use a new o-ring around the housing pilot or a new engine adapter gasket. Install the engine adapter onto the engine. Note that newer engine adapter castings have the word ‘TOP’ cast into it. The oil breather designates the ‘top’ of the pump crankcase. Both ‘top’ sides must be matched for proper pump operation.

64


and piston shoe bearing race.

Figure 6.23 — Bearing Race Assemblies

- The inside diameter of the outer cam bearing race is larger than the piston shoe bearing race. - The piston shoe bearing race may be thicker than the other races. The chamfered edge of the bearing races must face AWAY FROM THE BEARING ROLLERS, as shown in Figure 6.23. Piston Oil Seals and Pistons Refer to Figure 6.24 for this procedure. 1. Pre-lubricate three (3) piston oil seals with 80W90 oil. Figure 6.24 — Piston Oil Seals

Item

Name

1

Engine adapter bearing race

2


3

Inner cam bearing race

4

Axial cam assembly

5

Outer cam bearing race

6

Axial cam bearing

7

Piston shoe bearing race

A

Larger inside diameter

Item

Name

B

Smaller inside diameter

1

C

Chamfer faces this way

Pilot spacer tang engaged in crankcase locating notch

2

Crankcase locating notch

3

Pump crankcase

4

High pressure oil seal

5

Pilot spacer

Note: inset at lower left shows bearing race cross-section and locations of chamfers.

NOTE: Bearing race inside dimensions are different. Follow this procedure or the parts won’t go together.

2. Press a seal into one of the piston bores provided on the pump crankcase, with the writing on the face of seal toward the installer. Press the seal in until it bottoms. Repeat this step for the two (2) remaining seals.

6. Install the engine adapter bearing race, followed by the engine adapter bearing and the inner cam bearing race. - The inside diameter of the engine adapter bearing race is larger than the cam bearing race.

3. Install the three (3) pilot spacers over the piston oil seals, as shown in Figure 6.24:

- The chamfered edge of the bearing races must face AWAY FROM THE BEARING ROLLERS. That is, the flat (unchamfered) side of the race must ride against the rollers, as shown in Figure 6.23.

a. The larger diameter flange of the pilot spacer mates with the crankcase bore. b. The pilot spacer locating tangs must engage the crankcase locating notch, as shown in Figure 6.24.

7. Install the outer cam bearing race, the axial cam bearing 65


3. Piston assemblies have an integral spring retainer ring. Install the small end of the tapered spring so that it contacts the spring retainer, as seen in Figure 6.25.

6. Install the thermal bypass piston and spring into the socket cast into the upper portion of the pump crankcase, as shown in Figure 6.27. A small amount of petroleum jelly will hold these parts in the crankcase during subsequent assembly tasks.

Figure 6.25 — Return Spring Orientation

Figure 6.27 — Thermal Bypass Spring and Piston

Item

Name

1

Return spring

2

Piston

Item

Name

4. Apply a small amount of SAE 80W90 oil to the lip of the oil seals and the piston surface.

1

Crankcase

5. Install each piston through the spring, crankcase, oil seal, and pilot spacer, as shown in Figure 6.26.

2


3


4

Thermal bypass o-ring

Figure 6.26 — Piston Installation

Item

Name

1

Return spring

2

Pump crankcase

3

Piston oil seal

4

Pilot spacer

5

Piston 66


Spacer Plate 1. Install the three (3) low pressure seals into the bores provided in the spacer plate. Make sure the seal’s groove side is inserted into the spacer plate bore, as shown in Figure 6.28.

High Pressure Seal Assembly Refer to Figure 6.29 for this assembly. Figure 6.29 — High Pressure Seal Assembly

Figure 6.28 — Low Pressure Seal Orientation

Item

Name

1

Low pressure seal

Item

Name

2

Spacer plate

1

High pressure seal

2

Bearing ring

3

Pump head

2. Align the mounting holes in the spacer plate with the threaded holes in the pump crankcase. Align the low pressure seal bores of the spacer plate with the pistons protruding from the crankcase. And align the thermal bypass piston with its seat on the spacer plate.

1. Insert a bearing ring into each of the head’s piston cylinders, small end first. Ensure that the ring is fully seated on its boss. 2. Pre-lubricate the three (3) high pressure seals with silicone spray.

With all components aligned, push down on the spacer plate. The pilot spacers should engage the low pressure seal bores of the spacer plate.

3. Insert a seal in each piston cylinder so that the groove side goes in first. A properly inserted seal has its flat side out and nearly flush with the machined head surface.

3. Ensure that the thermal bypass piston remains aligned with its mating seat on the spacer plate.

67


Check Valve Assembly Refer to Figure 6.30 for this assembly.

a. Check that the actuator is fully seated. b. Make sure the small actuating stem is installed into the actuator. Petroleum jelly may be used to ensure that the actuating stem stays in place for the remainder of the assembly process.

Figure 6.30 — Check Valve Assembly

3. Install the three (3) inlet check valves: a. Align a check valve with its bore in the pump head so that the o-ring end is up. b. Push the check valve down into the head until it seats. The valve will be just overflush with the surrounding machined surface. c. Install the two remaining inlet check valves in the same manner. 4. Install the three (3) outlet check valves: a. Position the pump head so that the outlet check valve ports are up. b. Install an o-ring seal into the bottom of each check valve port. c. Align a check valve with the port so that the o-ring end goes in first. d. Press the check valve into the bore. e. Ensure that an o-ring is installed on an outlet port cap. f. Hand thread the cap into the port containing an installed check valve.

Item

Name

1

Outlet check valve port cap

2

Cap o-ring

3

Check valve

4

Check valve o-ring

5

Pump head

6

Thermal actuator stem

7

Thermal actuator

g. Tighten the outlet port cap to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View) at the beginning of this chapter. Note that final tightening is best performed after the pump is completely reassembled. h. Repeat steps e to g to install the two remaining outlet check valves.

1 Lay the pump head on a flat surface so that its machined surfaces are up. 2. Press the thermal bypass actuator into its recess in the pump head. 68


High Pressure Outlet and Chemical Injection Assembly Refer to Figure 6.31 for this assembly.

a. Ball seat assembly, o-ring end first. b. Stainless steel ball. c. Trapped line pressure seat, slotted end first. d. Trapped pressure piston assembly, o-ring end first.

Figure 6.31 — High Pressure Outlet and Chemical Injection

e. Trapped pressure return spring 6. Ensure that an o-ring is installed on the chemical injection venturi. 7. Insert and hand thread the chemical injection venturi into the head. 8. Carefully tighten the venturi to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View) at the beginning of this chapter. Avoid stripping out the slot. Unloader Spindle Assembly Refer to Figure 6.32 for this assembly. Figure 6.32 — Unloader Spindle Assembly

Item

Name

1


2

Check ball

3

Spring

4

Ball seat assembly

5

Unloader ball

6


7


8

Spring

Item

Name

9

Venturi assembly

1

Plastic cap

10

Head assembly

2


3

Unloader handle

4

Spring

5


6

Head assembly

1. Install the check ball into the chemical injection fitting, followed by the spring (with the small end of the spring towards the ball). 2. Install the chemical injection fitting into the pump head. Be careful not to drop the ball and spring.

1. Lightly coat the unloader spindle threads and o-rings with silicone spray.

3. Tighten the chemical injection nipple to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View) at the beginning of this chapter.

2. Insert the spindle into the bore provided on the pump head and hand start the threads.

4. Lightly coat the high pressure port components with silicone spray.

3. Tighten the spindle assembly to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View). The unloader spindle assembly is preset at the factory and does not need adjustment.

5. Insert the following components into the pump head in the order listed (refer to Figure 6.31): 69


Pump Head Installation Referring to Figure 6.33, install the pump head onto the pump spacer plate, as follows:

4. Align the pump head with the pistons protruding from the spacer plate and gently press the head into place.

CAUTION: Make sure the small stem of the thermal bypass actuator does not fall out during installation of the pump head.

Figure 6.33 — Pump Head Installation

5.Install six (6) M8-1.25 socket head cap screws with six (6) M8 washers. 6. Tighten the socket head screws in the order shown on Figure 6.34 to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View) at the beginning of this chapter. Figure 6.34 — Head Bolt Tightening Sequence

Item

Name

1

Crankcase assembly, including pistons and thermal bypass components

2

Spacer plate

3

Head gasket

4

Check valve o-rings (3)

5

Pump head assembly, including thermal bypass stem

6

Steel washer (6)

7

M8-1.25 socket head cap screw (6)

1. Install three (3) inlet check valve o-rings over the installed check valves using a dab of petroleum jelly. 2. Set the head gasket into place on the spacer plate with its holes properly aligned with mating spacer plate holes. 3. Ensure that the thermal bypass piston is properly aligned with its seat in the spacer plate.

70


Main Component Assembly Before installing the pump onto the engine, place the engine with its shaft in a vertical position and facing the installer. Make sure the engine adapter has been properly installed to the engine. Also check that the axial cam drive components are installed properly. The pump may now be installed as follows:

Figure 6.36 — “Jacking” Bolt Locations

1. Install a new o-ring seal around the mounting flange of the pump crankcase. 2. To aid reassembly, apply a dab of petroleum jelly to the piston pivot shoes, in the area indicated by item 1 in Figure 6.35. Figure 6.35 — Piston Pivot Shoes

5. Lower the pump toward the engine adapter. Align the crankcase and engine adapter mounting holes and also position the three piston pivot shoes so that they engage the axial cam bearing race properly. 6. When you are sure the pump crankcase and piston pivot shoes are properly aligned and positioned, thread the two long hex head bolts into the engine adapter mounting holes. 7. Visually verify that the piston shoes remain properly seated on the bearing race as you tighten the two screws alternately.

3. Place the piston pivot shoes onto the tips of the three pistons. The grease should hold the shoes in place. 4. Insert two (2) M6-1.0 x 45mm hex head bolts through mounting holes in the pump crankcase, 180° apart, and at the locations shown in Figure 6.36. These are the two long “jacking” screws.

8. When the two jacking bolts are tight, install four (4) M61.0 socket head cap screws through the mounting holes of the pump crankcase. Thread them into the mounting holes of the engine adapter until they are snug. 9.Remove the two (2) “jacking” hex head bolts and replace them with the two (2) remaining M6-1.0 socket head cap screws. 10. When all six (6) socket head cap screws are snugged down, tighten them to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View) at the beginning of this chapter.

71


Oil Fill Before filling the pump crankcase with oil, ensure that the head screws, outlet port caps, and crankcase screws are tightened to the torque value specified in the Torque Chart, found on Figure 6.2 (Exploded View) at the beginning of this chapter. Referring to Figure 6.37, insert a funnel into the Oil Fill/Breather cap threaded opening at top of the pump crankcase. Add the amount and type of oil recommended in the table in Part 2 of the Common Pump Components section, earlier in this manual. Figure 6.37 — Pump Oil Fill Location

Item

Name

1

Funnel

2

Breather cap

3

Assembled pump/crankcase

72



Possible Cause

Corrective Action

1. Water leakage at mating flanges.



b. Damaged head.

b. Replace head.



a. Chemical injection fitting improperly torqued.

a. Torque fitting.

b.Check ball missing.

b. Replace check ball and spring.

c. Check ball stuck.

c. Remove, clean and replace fitting, ball and spring.



b. Defective head gasket.

b. Install good head gasket.

c. Damaged head.

c. Replace head.

d. Missing or damaged o-rings.

d. Install new o-rings.

a. Connector not properly seated.




a. Defective or missing head gasket.

a. Install new head gasket.

b. Head bolts improperly torqued.

b.Torque head bolts properly.

c. Porosity in spacer plate.

c. Replace spacer plate.

a. Thermal bypass piston missing or defective.

a. Install thermal bypass piston.

b. Bad or missing thermal bypass piston spring.

b. Install new spring.

2. Water leakage from chemical

injector.

3. Water leakage between pump head

and spacer plate.

4. Water leaks from high pressure out

connector.

5. Water leaking out of head bolts.

6. Water leaking out behind spacer

plate.

c. Bad o-ring on thermal bypass piston. d. Low pressure water seals leaking.

73

c. Install new o-ring. d. Install new low pressure seals.


Part 5 - Troubleshooting (Continued)

Problem

Possible Cause

Corrective Action

7. Oil leak between engine and engine adapter.

a. Defective or missing engine adapter oring or gasket.

a. Install new o-ring or gasket.

b. Engine adapter cap screws not tightened properly.


8. Oil leak between engine adapter and pump crankcase.





9. Oil leak between pump crankcase and spacer plate.

a. Missing or bad low pressure seals.

a. Install new seals.

b. Missing or bad piston oil seal.

b. Install new oil seals.

c. Cracks in casting.

c. Replace cracked casting.

a. Nozzle is set to low pressure mode. 10. Pump does not produce pressure, exhibits erratic pressure, chatters or has b. Incorrect spray nozzle is used. a low water volume. c. Spray nozzle is obstructed.


a. Reset nozzle to high pressure. b. Replace with correct nozzle. c. Clear obstruction from nozzle.


d. Clear inlet.






g. Clean strainer.




i.

j. Unloader-regulator valve set wrong.

j. Set valve to high pressure.

k. Obstructed nozzle oe chemical venturi.

k. Remove, clean and replace chemical injection components.







74


Portable Pressure Washer Familiarization and Troubleshooting Guide Section 7 • Large Frame Pump

LARGE FRAME PUMP This section describes the large frame pump assemblies powered by gasoline or diesel engines intended for use in heavy duty applications. This large frame pump may also be referred to as a ‘GPW’ pump. Most of the information previously printed in publication 97492 will be found here. The large frame pump has the following features: • 1500 to 3000 PSI water pressure • 2.0 to 3.0 Gallons per minute flow • Axial Cam Design • QPQ, Stainless Steel, or Ceramic Pistons • Easy Start Unloader • Adjustable Output Water Pressure • Chemical Injection System available • Brass heads (above 2200psi) • Aluminum heads (2200psi and below) • Thermal Relief Valve • Oil Bath Drive System

Part 1 - Specifications and Views This section presents the torque and performance specifications for Generac Portable Products® large frame pumps. Also presented are sectional and exploded views of this type of pump assembly. Pump Assembly Part No.

Rated Pressure+

Engine Shaft

Pump Head

Flow Rate*

Piston Material

Oil Type/ Capacity

21300A 21300B 21300D 21300E 95523A 95523B 95523C 95523D 95523E 95523F 95523G 97239A 97239B 97239C 99750A 99750G

2250 2700 2600 2900 1500 1800 1500 1500 2000 2200 2500 1600 1900 2600 2500 3000

Straight Straight Tapered Tapered Straight Straight Straight Straight Tapered Tapered Tapered Straight Straight Straight Tapered Tapered

Aluminum Brass Brass Brass Aluminum Aluminum Aluminum Aluminum Brass Brass Brass Aluminum Aluminum Brass Brass Brass

2.2 2.5 2.6 2.9 2.0 2.3 3.0 2.0 3.0 3.0 3.0 2.0 2.5 3.0 3.0 2.5

Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic

80W90/300ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml 80W90/285ml

Performance Specifications + Pressure (in pounds per square inch) is adjustable up to the unit's rated pressure. * Flow rate is given in gallons per minute. Pump assemblies are listed by part number and were current at time of publication. Other pump assemblies will become available as our product evolves. 75



A typical large frame pump is shown in cross-sectional view in Figure 7.1.

Figure 7.1 — Large Frame Pump (cross-sectional view)

76


Sectional View Parts List

Item

Qty

Description

1

1

Unloader-pressure regulator assembly

2

3

Socket head cap screw, M6-1.0 x 45mm

3

3


4

1

Pump head assembly

5

1

O-ring

6

3

Piston pivot shoe

7

1

Axial cam bearing

8

1

9

Item

Qty

Description

14

1

Straight engine shaft adapter

15

1

C-ring cam retainer

16

1

Engine adapter gasket

17

4


18

6


19

6

Socket head cap screw, M6-1 x 20mm

20

6

Socket head cap screw, M8-1.25 x 0.75

Axial cam

21

6


1

Engine adapter

22

1

Engine adapter o-ring

10

1


23

1

Tapered engine shaft adapter

11

1

Thrust washer

24

4

O-ring

12

1

Engine pilot sleeve

25

4

Button head cap screw, 5/16” - 24

13

1

Retainer washer

26

1

Belleville washer

27

1

Jam nut

77


Exploded View

A typical large frame pump is shown in exploded view in Figure 7.2.

Figure 7.21 — Large Frame Pump (exploded view)

Torque Chart The larger view above is a typical tapered engine shaft parts group. The inset is a typical straight engine shaft adapteraxial cam parts group. Certain components have been changed, added, or deleted since this large frame pump began production. Always refer to the Owner’s Manual shipped with each model pressure washer for appropriate part number references.

78

Item

Torque Value

2

5-8 ft-lbs

17

12-18 ft-lbs

19

5-8 ft-lbs

20

18-20 ft-lbs

25

8-10 ft-lbs

30

10-15 in-lbs w/Loctite

41

in Aluminum head:12-15 ft-lbs

41

in Brass head: 15-17 ft-lbs

49

5-8 ft-lbs

Drain plug

180 in-lbs max. (if equipped)



Qty

Description

Item

Qty

Description

1

1

Unloader-pressure regulator assembly

26

1

Belleville washer

27

1

Jam nut

2

3

Socket head cap screw, M6-1.0 x 45mm

28

3

Piston

29

3


30

1

Breather cap

31

1

Pump crankcase

32

3

Oil piston seal

33

3

Pilot spacer

34

3

Low pressure water seal

35

3

High pressure seal

36

3

Bearing seal ring

37

3

Backup ring

38

3

O-ring

39

3

High pressure port tower

40

3

Check valve guide

41

1

Pipe plug, 1/8 NPT

42

1

Cylinder head

43

1

Handle

44

3

Check valve guide

45

3

Check valve poppet

46

3

O-ring

47

3

Backup ring

3

3


4

1

Pump head assembly

5

1

O-ring

6

3

Piston pivot shoe

7

1

Axial cam bearing

8

1

Axial cam

9

1

Engine adapter

10

1


11

1

Thrust washer

12

1

Engine pilot sleeve

13

1

Retainer washer

14

1

Straight engine shaft adapter

15

1

C-ring cam retainer

16

1


17

4

Socket head cap screw, 5/16”-24 x 0.75

18

6


19

6

Socket head cap screw, M6-1 x 20mm

20

6

Socket head cap screw, M8-1.25 x 0.75

48

3

Check valve support

49

1

Garden hose connector

21

6


50

1


22

1

Engine adapter o-ring

51

1

Head gasket

23

1

Tapered engine shaft adapter

52

1

Spacer plate

24

4

O-ring

53

1

O-ring

25

4

Button head cap screw, 5/16”-24 x 0.75

54

1


55

1


79





DANGER: The pump removal procedures described in this section must be followed carefully or personal injury could result. During removal of the pump, extremely powerful springs tend to separate the pump head from the engine adapter. Failure to follow the described procedure may result in a forceful separation of the head from the adapter. Because different pressure washer models may use different engines, some differences may exist between pressure washer pumps. Such differences will be found primarily in the engine adapter section of the pump. For example, some engines feature a tapered crankshaft while others may be equipped with a straight shaft. And, of course, the engine adapter itself must be designed for attachment to a specific engine. In addition, some pumps may be equipped with ball cam bearings while others have roller cam bearings. Differences may also exist in pump head components. The axial cam used on a pump rated 2.5 gallons per minute, for example, must necessarily be different than the axial cam used on a pump rated at 3 gallons per minute.

3. As depicted in Figure 7.4, start backing out the two bolts installed in (1.). Alternate between the two bolts, using them as a “jacking” device to separate the pump crankcase from the engine adapter while relieving spring tension from between these two components.

Special tools needed: • Special engine shaft adapter puller tool, Generac Portable Products® part number SRV95523

Figure 7.4 - Head Screw Removal

• Dead blow mallet • 0.25” dia. 7” long brass rod Pump Head Before removing the pump head, disconnect the inlet water hose from the pump’s water inlet. Also disconnect the spray gun high pressure hose from the pump’s water outlet connector. With the hoses disconnected, remove the pump: 1. Referring to Figure 7.3, replace the two (2) M6-1.0 cap screws with two (2) M6-1.0 x 45mm hex head bolts. 2. Ensure the two bolts described in (1.) above are tight, then remove the four (4) remaining M6-1.0 cap screws.

CAUTION: Do Not attempt to disassemble the pump without installing two longer screws, as described, to relieve the spring tension. 80


4. As the pump crankcase is separated from the engine adapter, three (3) piston pivot shoes (shown in Figure 7.5) will fall out. Retain the shoes for later inspection and installation.

3. Remove the engine adapter bearing assembly.

Figure 7.5 - Pivot Shoe

4. Remove the M16-1.50 Jam Nut and the Belleville washer. 5. Remove the axial cam. 6. Referring to Figure 7.7, use a special engine shaft adapter puller tool to remove the engine shaft adapter: Figure 7.7 - Puller Tool on Tapered Shaft

Axial Cam Drive Components - (Tapered Engine Shaft) On units with tapered engine shafts, the engine shaft adapter is retained to the engine shaft by means of an M16-1.50 Jam Nut and a Belleville washer. To remove the axial cam drive components from the engine shaft, proceed as follows, referring to Figure 7.6: Figure 7.6 - Axial Cam Drive Components (Units with Tapered Engine Shaft)

a. Attach the tool to the threaded portion of the engine shaft adapter. b. Turn the bolt on the tool firmly against the engine tapered shaft, putting tension on the engine adapter. Then strike the bolt head with a dead blow mallet.

Item

Name

1

O-ring

2

Engine Adapter

3

Roller Thrust Bearing

4

Engine Shaft Adapter

5

Axial Cam

6

Bearing Assembly

7

Belleville washer

8

Jam nut

c. Continue tightening the tool bolt against the engine shaft and striking with the mallet until the engine shaft adapter is completely free of the engine shaft. Remove the engine shaft adapter. 7. Remove four (4) 5/16”-24 socket head or button head cap screws that retain the engine adapter to the engine. Remove the engine adapter. The large o-ring seal or gasket found between the engine adapter flange and pump crankcase flange can also be removed. 8. If necessary, remove the engine adapter sleeve from an older-model engine adapter. New models have an integral engine adapter pilot.

1. Remove the pump head, as described previously. 2. Remove the axial cam bearing assembly. Some models will have a ball bearing, some a roller bearing. KEEP BEARING RACES AND BEARINGS TOGETHER AS A SET. 81


Pistons and Piston Springs Refer to Figure 7.9 for this disassembly. The three (3) pistons along with their springs can be removed from the pump crankcase by grasping the springs and pulling straight out.

9. Remove all traces of the engine adapter gasket or o-ring. Use a new gasket or o-ring each time the engine adapter is installed. Axial Cam Drive Components - (Straight Engine Shaft) On units with straight engine shafts, proceed as follows, referring to Figure 7.8.

Figure 7.9 - Piston Assembly

Figure 7.8 - Axial Cam Drive Components (Units with Straight Engine Shaft)

Item

Name

1

Engine adapter

2


3

C-ring cam retainer

4

Washer retainer

5

Thrust washer

6


7

Axial cam

8

Piston pivot bearing assembly

Item

Name

1

Return spring

2

Piston

3

Retainer

4

Lock ring

Newer model pumps have the retaining ring attached permanently to the piston (upper illustration). On older models, the springs are retained by spring retainers and a lock ring. It is not necessary to remove the spring retainer and lock ring unless they are obviously damaged and require replacement. Regulator/Unloader Valve Referring to Figure 7.10, remove the three (3) M6-1.00 unloader cap socket screws and M6 ribbed lock washers. Figure 7.10 — Unloader Valve Removal

1. Remove the axial cam bearing, the axial cam, and the engine adapter bearing assembly as a unit. Bearings may be either ball or roller bearing type, depending on the pump model. 2. Remove the engine shaft adapter, thrust washer and retainer washer 3. Remove the four (4) 5/16”-24 socket head or button head cap screws that retain the engine adapter to the engine. The engine adapter can now be removed. 4. Remove the engine adapter gasket completely. 82


Figure 7.11 depicts the Unloader/Pressure Regulator Valve assembly in cross sectional view. Figure 7.11 - Pressure Regulator/Unloader Valve Assembly

Item

Name

Item

Name

Item

Name

1

Adapter housing

11

Guide stem

21

Stainless steel spring

2

O-ring

12

Support ring

22

Chemical injector body

3

Bushing

13

Piston

23

Stop ring

4

11/32” ball

14

Zinc plated nut

24

Washer

5

Magnet

15

Regulator spring

25

Hose barb coupling

6

Magnet stop ring

16

Spring guide stop

26

Adjusting screw

7

Guide

17

Knob insert

27

Chemical injection knob

8

Guide plug

18

Pressure knob

28

Hose barb connection

9

Support ring

19

Self locking nut

29

7/32” ball

10

Elastic pin

20

Piston seal

30

Taper spring

83


Cylinder Head

To remove the three (3) inlet (low pressure) check valves, refer to Figure 7.14 and proceed as follows:

NOTE: Some pump models feature a BRASS cylinder head, some an ALUMINUM cylinder head.

Figure 7.13 — Check Valve Puller

To remove the pump cylinder head, refer to Figure 7.12 and proceed as follows: 1. Remove six (6) M8-1.25 socket head cap screws and M8 ribbed lock washers. Figure 7.12 — Pump Head Removal

1. Insert the ‘T’ handle through the puller tool thimble (item 1). 2. Turn the puller upper tee handle clockwise until the Figure 7.14 — Inlet Check Valve Removal

Item

Name

1

Spacer plate

2

Head gasket

3

Thermal bypass

4

Plug

5

Cylinder head

6

Lock washer

7


8

Inlet water connector/filter

Item

Name

1

Puller tool

2

O-ring

3

Check valve

4

Backup ring

puller threads have engaged the check valve threads.

2. Remove the cylinder head and head gasket. To disassemble the head and remove the check valves, refer to Figures 7.13 to 7.15 and proceed as follows:

NOTE: Do not turn the tool in too far. An engagement of 2 or 3 threads is sufficient.

A special puller tool (included in Generac Portable Products® kit number SRV95523) is used to remove the inlet and outlet check valves. As shown in Figure 7.13, the tool consists of a threaded (7/16”-20) tee handle arrangement.

3. With the puller threads engaged in the check valve threads, hold the upper ‘T’ handle and keep it from turning while you turn the tool lower ‘T’ handle clockwise. 4. Repeat steps 2 and 3 for the other inlet check valves.

Three (3) inlet and three (3) outlet check valves are threaded (7/16”-20) to accept the threaded tee handle. 84


Thermal Bypass Actuator Removal Refer to Figure 7.16 and:

To remove the three (3) outlet (high pressure) check valves, refer to Figure 7.15 and proceed as follows:

Figure 7.16 — Thermal Bypass Actuator Removal

Figure 7.15 — Outlet Check Valve Removal

Item 1 2 3 4

Name Puller tool Backup rings Check valve O-rings

Item

Name

1

Pump crankcase

2

Spring

3

O-ring

1. Insert the ‘T’ handle through the puller tool thimble (item 1).

4

Spacer plate

5

Head gasket

2. Turn the puller lower tee handle fully counterclockwise.

6

Pump head

3. Insert the puller down through the high pressure port tower.

7

Insert brass rod here

8


4. Turn the puller upper tee handle clockwise until the puller threads have engaged the check valve threads.

1. Remove the small bypass piston. 2. Obtain a brass rod approximately 1/4” (5.35 mm) in diameter and 7” long.

NOTE: Do not turn the tool in too far. An engagement of 2 or 3 threads is sufficient.

3. Insert rod from the unloader/pressure regulator valve side of the head.

5. With the puller threads engaged with the check valve threads, turn the tool lower handle clockwise to remove the check valve. Both the high pressure port tower and the outlet check valve will be removed.

4. Tap the rod gently with the dead blow hammer to free the actuator.

6. Repeat steps 2 to 5 for the other outlet check valves.

85


Spacer Plate Referring to Figure 7.17, remove the spacer plate from between the crankcase and pump head, as follows:

1. If present, remove two (2) M5-0.80 x 20mm truss head bolts along with the o-ring seal on each bolt. 2. Separate the spacer plate from the crankcase. 3. Remove the three (3) white pilot spacers.

Figure 7.17 - Spacer Plate Removal

4. Remove the three (3) piston oil seals from the pump crankcase. 5. Remove the thermal bypass piston and the thermal bypass spring. 6. Completely remove all traces of the head gasket from the mating surface.

Item

Name

1


2

Thermal bypass piston & o-ring

3

Spacer plate

4

Low pressure seal

5

Pilot spacer

6

Piston oil seal (in crankcase)

86


Part 3 - Inspection

Figure 7.19 — Inlet Check Valve

Seals, O-Rings, and Gaskets Replace seals and gaskets during the reassembly process. Oil Seals Each of the three (3) pump pistons pass through an oil seal in the pump crankcase. The inset in Figure 7.18 shows that the lip of the the spacer plate low-pressure oil seal points into the opening. Figure 7.18 — Oil Seals

Outlet Check Valve Seals The three (3) outlet check valves are assembled into the head with the components shown in Figure 7.20. Figure 7.20 — Outlet Check Valve Parts

Item

Name

1

Spacer plate

2

Oil seal

Inlet Check Valve Seals An inlet check valve is shown in Figure 7.19. The three (3) inlet check valves are pressed into cylindrical openings machined in the pump head, followed by an o-ring seal, backup ring, and check valve seat support.

87

Item

Name

1

High pressure seal

2

Bearing seal ring

3

Backup ring

4

O-ring

5

High pressure port tower

6

Check valve

7

Cylinder head


Head Gasket A head gasket, depicted in Figure 7.21, is installed between the pump head and the spacer plate. Replace the gasket each time the pump is reassembled.

Engine Adapter, Pump Crankcase, Spacer Plate and Head Clean all parts. Inspect carefully for cracks, damage, and so forth. Check for corrosion. Replace any damaged, defective, or corroded part as necessary.

Figure 7.21 — Two Types of Head Gaskets

Axial Cam Drive Components Units with Tapered Engine Shaft: If so equipped, carefully inspect the engine adapter sleeve (seen later in Figure 7.28). Replace if worn or damaged. The engine adapter sleeve is retained to the engine adapter with Permabond No. HM160 LOCTITE. Referring to Figure 7.23, inspect the engine adapter bearing and the axial cam bearing assemblies for wear, damage, freedom of rotation, and evidence of overheating. Replace any damaged or defective bearing assembly. Figure 7.23 - Axial Cam Drive Components (Units with Tapered Engine Shaft)

Engine Adapter Gasket On models so equipped, replace the engine adapter gasket, seen in Figure 7.22, whenever the engine adapter has been removed. Figure 7.22 — Engine Adapter Gasket

Item

Name

1

O-ring

2

Engine Adapter

3

Roller Thrust Bearing

4

Engine Shaft Adapter

5

Axial Cam

6

Bearing Assembly

Check the axial cam for wear, damage, scoring, overheating, grooving, etc. Replace if worn excessively or damaged.

Later model pumps use a flange o-ring and bolt head o-ring seals instead of the engine adapter gasket.

Inspect the engine shaft adapter. Check for evidence of scoring, wear, damage, overheating. Replace if necessary. 88


Piston & Spring Assemblies Referring to Figure 7.9 (seen earlier), inspect the three (3) pistons carefully. Replace all three pistons and piston shoes as a set if any one piston is scratched, dented, chipped, or otherwise damaged.

Inspect the jam nut and the Belleville washer for wear or damage. Replace if necessary. Units with Straight Engine Shaft: Referring to Figure 7.24, carefully inspect the engine adapter bearing and the axial cam bearing assemblies for wear, damage, freedom of rotation, or evidence of overheating. Replace any damaged or defective bearing assembly.

CAUTION: Do not strike a piston with any object or use a piston to strike any object. Do not drop the piston. Dropping the piston will result in damage.

Figure 7.24 - Axial Cam Drive Components (Units with Straight Engine Shaft)

Measure the piston diameter and the piston length (as shown in Figure 7.25). If the values are not within the tolerances specified below, replace all three pistons as a set: Figure 7.25 — Piston Dimensions

Piston diameter: 14.977 mm to 14.985 mm Item

Name

1

Engine adapter

2


3

C-ring cam retainer

4

Washer retainer

5

Thrust washer

6


7

Axial cam

8

Piston pivot bearing assembly

Piston length: 86.65 mm to 90.05 mm Inspect the piston pivot shoes, depicted in Figure 7.26. Replace pistons and shoes as a set, if damaged. Figure 7.26 — Piston Pivot Shoe

Check the engine shaft adapter assembly (items 3, 4, 5, and 6), which is a part of the axial cam. Since these parts require factory assembly, they must be replaced as a set. The adapter has a built-in key which mates with an engine shaft keyway. Replace if worn or damaged.

89


On units so equipped, inspect the three (3) lock rings and the three (3) spring retainers; replace if damaged. Inspect the three (3) piston springs. Ends must be closed and ground square. Check spring free length and load length as follows, referring to Figure 7.27: Figure 7.27 — Piston Return Spring

Item

Name

1

Free length

2

Load length

1. Free length should be 62.57 mm (2.463”). 2. Apply a force of 51.0 to 56.4 pounds (227.2 to 251.1 Newtons). At the stated load, spring length should be 39.8 mm (1.567”). Replace any spring that is damaged or broken. replace spring if free length or load length is not as stated. Unloader-Pressure Regulator Valve Refer to Figure 7.11, seen earlier. Replace any damaged or defective parts as necessary.

90


Part 4 - Reassembly

Figure 7.29 — Engine Adapter Attachment (Units with Tapered Engine Shaft)

Refer to the Torque Specifications provided on the pump sectional view found at the beginning of this section when reassembling this product. Engine Adapter Units with Tapered Engine Shaft: 1. Units with a tapered engine shaft may have an engine adapter sleeve. Referring to Figure 7.28, apply LOCTITE Permabond No. HM160 to the outside of the larger diameter of the sleeve, then install the sleeve into the engine adapter as follows: Figure 7.28 — Engine Adapter Sleeve

Item

Name

1

Apply Loctite around the larger circumference of the ring in this area.

Item

Name

1


2

Engine adapter

3


4


5

Axial cam

6


7

Belleville washer

8

Jam nut

9


10

Lock washer

b. Orient the “TOP” mark in engine adapter with top of engine and fasten the engine adapter to the engine with four (4) 5/16”-24 socket head cap screws and four (4) M8 ribbed lock washers.

a. From the inside of the engine adapter, press the smaller-diameter end of the adapter sleeve into the large bore of the engine adapter.

c. Tighten the cap screws to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.

b. Tap the adapter sleeve into the engine adapter bore until it seats flush against the inside machined surface of the engine adapter.

NOTE: When installing the engine adapter having the glued-in sleeve, be sure to use the correct socket head cap screws. Pump assemblies used on engines with straight (non-tapered) shafts use 5/16”-24 x 3/4” long cap screws. Pumps on engines with tapered shafts use 5/16”-24 x 1” long cap screws.

2. Position the engine with engine shaft facing up. Referring to Figure 7.29: a. Use a new adapter gasket and install the engine adapter onto the engine.

3. Install the engine shaft adapter over the tapered engine shaft, as shown in Figure 7.29. 91


4. Install the engine adapter bearing race, followed by the engine adapter bearing and the inner cam bearing race. Refer to Figure 7.30.

5. Install the axial cam (with cam surface facing you) over the engine shaft adapter. Push the cam toward the engine until it seats against the engine adapter bearing race. 6. Again referring to Figure 7.30. install the outer cam bearing race, axial cam bearing and piston shoe bearing race.

Figure 7.30 — Bearing Race Assembly

a. For ROLLER BEARINGS, the chamfered edge of the bearing races must face AWAY FROM THE BEARING ROLLERS. That is, the flat (unchamfered) side of the race must ride against the rollers. The inside diameter of the outer cam bearing race is larger than the piston shoe bearing race. b. For BALL BEARINGS, the bearing races are grooved to accept the bearing balls. MAKE SURE THE BEARING BALLS ARE RIDING IN THE BEARING RACE GROOVES.

Item

Name

1

Engine adapter bearing race

2


3

Inner cam bearing race

4

Axial cam assembly

5

Outer cam bearing race

6

Axial cam bearing

7

Piston shoe bearing race

A

Larger inside diameter

B

Smaller inside diameter

C

Chamfer faces this way

7. Install the Belleville washer and the M16-1.50 jam nut over the engine tapered shaft. Tighten the M16-1.50 jam nut to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.

Note: Inset at lower left shows bearing race cross-section and locations of chamfers a. For ROLLER BEARINGS, the chamfered edge of the bearing races must face AWAY FROM THE BEARING ROLLERS. That is, the flat (unchamfered) side of the race must ride against the rollers. b. For BALL BEARINGS, the bearing races are grooved to accept the bearing balls. MAKE SURE THE BEARING BALLS ARE RIDING IN THE BEARING RACE GROOVES. 92


Units with Straight Engine Shaft:

When installing the engine adapter having the gluedin sleeve, be sure to use the correct socket head cap screws. Pump assemblies used on engines with straight (non-tapered) shafts use 5/16”-24 x 3/4” long cap screws. Pumps on engines with tapered shafts use 5/16”-24 x 1” long cap screws.

Two types of engine adapters have been produced - one that uses an engine adapter gasket and socket head cap screws, and one that uses an o-ring and button head fasteners. 1. To assemble units having an engine adapter gasket, refer to Figure 7.31:

2. To assemble units having an O-ring seal and button head cap screws with o-ring seals, refer to Figure 7.32:

Figure 7.31 — Axial Cam Drive Components (Units with Straight Engine Shaft)

Item

Name

1


2

Engine adapter

3


4

C-ring cam retainer

5 6

Figure 7.32 — Axial Cam Drive Components (Units with Straight Engine Shaft and O-Ring Seal)

Item

Name

1

O-ring

2

Engine adapter

Washer retainer

3


Thrust washer

4

C-ring cam retainer

7


5

Washer retainer

8

Axial cam

6

Thrust washer

9


7


10

Lock washer

8

Axial cam

11


9


10


11

O-ring

a. Use a new adapter gasket and install the engine adapter onto the engine.

a. Use a new O-ring around the housing pilot and install the engine adapter onto the engine.

b. Retain the engine adapter to the engine with four (4) 5/16”-24x 3/4” socket head cap screws and for (4) M8 ribbed lock washers.

b. Retain the engine adapter to the engine with four (4) 5/16”-24x 3/4” button head cap screws and four (4) o-rings.

c. Tighten the cap screws to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.

c.

93

Tighten the cap screws to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.


NOTE: When installing the engine adapter having the o-ring seals, be sure to use the correct button head cap screws. DO NOT use any other type fastener.

Piston Oil Seals and Pistons Refer to Figure 7.33 for this procedure. Figure 7.33 — Oil Seals & Pilot Spacers

3. Install the engine shaft adapter over the engine shaft, as shown in Figure 7.31 or 7.32. 4. Install the engine adapter bearing race, followed by the engine adapter bearing and the inner cam bearing race. Refer to Figure 7.30. a. For ROLLER BEARINGS, the chamfered edge of the bearing races must face AWAY FROM THE BEARING ROLLERS. That is, the flat (unchamfered) side of the race must ride against the rollers. b. For BALL BEARINGS, the bearing races are grooved to accept the bearing balls. MAKE SURE THE BEARING BALLS ARE RIDING IN THE BEARING RACE GROOVES. 5. Install the axial cam assembly. The factory-installed adapter has a built-in key which must engage with a keyway on the straight (non-tapered) engine shaft. Push the cam toward the engine until it seats against the engine adapter bearing race. 6. Again referring to Figure 7.30, install the outer cam bearing race, axial cam bearing and piston shoe bearing race. a. For ROLLER BEARINGS, the chamfered edge of the bearing races must face AWAY FROM THE BEARING ROLLERS. That is, the flat (unchamfered) side of the race must ride against the rollers.

Item

Name

1

Pilot spacer tang engaged in crankcase locating notch

2

Crankcase locating notch

3

Pump crankcase

4

High pressure oil seal

5

Pilot spacer

1. Pre-lubricate three (3) piston oil seals with 80W90 oil. 2. Press a seal into one of the piston bores provided on the pump crankcase, with the writing on the face of seal toward the installer. Press the seal in it bottoms. Repeat this step for the two (2) remaining seals.

The inside diameter of the outer cam bearing race is larger than the piston shoe bearing race. b. For BALL BEARINGS, the bearing races are grooved to accept the bearing balls. MAKE SURE THE BEARING BALLS ARE RIDING IN THE BEARING RACE GROOVES.

3. Install the three (3) pilot spacers over the piston oil seals, as shown in Figure 7.33: a. Larger diameter flange of the pilot spacers must face downward (away from installer). b. Two small locating tangs on the pilot spacers must fit inside locating notch of the pump crankcase, as depicted in Figure 7.33.

94


4. If the piston assemblies use a lock ring and have been disassembled, assemble them as follows:

Figure 7.35 — Piston Installation

a. Install a retainer ring into the groove at one end of each piston. b. Slide the piston spring retainer up the piston until it contacts the retainer ring. Retainer must be installed exactly as shown in Figure 7.34. c. Springs are tapered. Install small end of tapered spring so that it contacts the spring retainer. 3. If the piston assemblies have an integral spring retainer ring, install the small end of the tapered spring so that it contacts the spring retainer. Figure 7.34 — Return Spring Orientation

Item

Name

1

Lock ring

2

Spring retainer

3

Return spring

4

Piston

Item

Name

1

Return spring

2

Pump crankcase

3

Piston oil seal

4

Pilot spacer

5

Piston

6. Install the thermal bypass piston and spring into the bore provided in the center of the pump crankcase, as shown in Figure 7.36. Figure 7.36 — Thermal Bypass Components

4. Apply a small amount of SAE 80W90 oil to the lip of the oil seals and the piston surface. 5. With spring in place around piston as shown in Figure 7.34, install the piston through the crankcase, oil seal, and pilot spacer, as shown in Figure 7.35.

95

Item

Name

1

Pump crankcase

2


3


4

O-ring


Pump Head Assembly 1. Install an o-ring and backup ring on all check valves, as shown in Figure 7.38.

Spacer Plate 1. Referring to Figure 7.37, install the three (3) low pressure seals into the bores provided in the spacer plate.

Figure 7.38 — Check Valve O-Ring Assembly

Figure 7.37 — Inlet Check Valve Seat Supports

Item

Name

1

Low pressure seal

2

Spacer plate

3

Check valve support

Item

Name

1

O-ring

2

Backup ring

2. To install the three (3) inlet check valves, along with their o-ring seals, use a 7/16”-20 bolt of sufficient length along with a nut, washer, and one of the high pressure port towers, similar to that depicted earlier in Figure 7.15. a. Thread a jam nut onto the bolt, then the washer. b. Install the high pressure port tower over the bolt until it contacts the washer and leaves 4 or 5 bolt threads exposed.

2. Align the low pressure seal bores of the spacer plate with the pistons protruding from the pump crankcase. With mating holes aligned, push down on the spacer plate. The low pressure seal bores of the spacer plate should engage the pilot spacers.

c. Thread the 7/16”-20 bolt into the female threads of the inlet check valve. Then use the jam nut to fingertighten the high pressure port tower against the valve backup ring. Make sure the high pressure port tower is snugged firmly against the backup ring.

3. If present in older-model units, install an o-ring over the two M5-0.80 x 20mm truss head screws. Install and tighten the two truss head screws into holes provided in the spacer plate and threaded holes in the pump crankcase.

Again, refer to Figure 7.15 for a depiction of this assembly’s appearance. d. Lubricate an inlet check valve, seal, and backup ring with silicone spray.

4. The inlet check valve seat supports are installed over the spacer place, as shown in Figure 7.37, with the large diameter end toward the crankcase.

96


e. Align the inlet check valve with its bore in the pump head, as shown in Figure 7.39. Push the check valve, along with its seal and backup ring, down into the check valve bore.

d. Insert the 7/16”-20 bolt/jam nut/washer down through the bore of the high pressure port tower and engage the bolt threads with the internal threads of the outlet check valve. e. Snug the jam nut down against the washer to force the end of the tower firmly against the backup ring of the outlet check valve.

Figure 7.39 - Inlet Check Valve Installation

f. Lubricate an outlet check valve and tower with silicone spray. g. As shown in Figure 7.40, carefully align the check valve and tower with the high pressure bore provided in the pump head. Press the check valve and tower into the bore. h. Unscrew and withdraw the bolt, jam nut, and washer. i. Install the two remaining outlet check valves and towers in the same manner. Figure 7.40 - Outlet Check Valve Installation

f. Unscrew and withdraw the bolt, jam nut, and washer. g. Install the two remaining inlet check valves in the same manner. 3. Install the three (3) outlet check valves and three (3) high pressure port towers as follows: a. Install an o-ring seal and backup ring onto the high pressure port tower, similar to that seen earlier in Figure 7.38. b. Install a bearing seal ring into the high pressure port tower (seen in Figure 7.38). c. Install a high pressure seal into the high pressure port tower, over the bearing seal ring previously installed (Figure 7.38).

4. Press the thermal bypass actuator into its recess at the center of the pump head. Check that the actuator is fully seated. Make sure the small actuating stem is installed into the actuator. A small dab of petroleum jelly will help hold it in place.

97


Pump Head Installation Referring to Figure 7.41, install the pump head onto the pump spacer plate, as follows:

4. Install six (6) M8-1.25 socket head cap screws with six (6) M8 ribbed lock washers to retain the head. 5. Tighten the socket head screws in the order shown on Figure 7.42 to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.

Figure 7.41 — Pump Head Installation

Figure 7.42 — Head Bolt Tightening Sequence

Item

Name

1

Spacer plate

2

Head gasket

3


4

Pump head

5

Lock washer

6


7*

O-ring

8*

Unloader valve spindle seat

9

Inlet water connector/filter

6. Install the garden hose connector with filter screen onto the pump head.

* May not be present, depending on age of pump 1. If equipped, check that three (3) inlet check valve seat supports are properly installed into the bores provided on the spacer plate. 2. Set the head gasket into place on the spacer plate with its holes properly aligned with mating spacer plate holes. 3. Align the pump head with high and low pressure bores of the spacer plate and set the head into place.

CAUTION: Make sure the small stem of the thermal bypass actuator does not fall out during installation of the pump head. 98


Unloader-Pressure Regulator Valve 1. Install the valve spindle with o-ring seal into the bore provided on the pump head (illustrated in Figure 7.41).

Main Component Assembly Before installing the pump onto the engine, place the engine with its shaft in a vertical position and facing the installer. Make sure the engine adapter has been properly installed. Check that the axial cam drive components are installed properly. The pump may now be installed as follows:

2. Install the assembled unloader-pressure regulator valve. Retain with three (3) M6-1.00 socket head cap screws, as shown in Figure 7.43.

1. Install a new o-ring seal around the mounting flange of he pump crankcase.

Figure 7.43 — Unloader-Pressure Regulator

2. To aid reassembly, apply a dab of axle grease or petroleum jelly to the piston pivot shoes, as indicated by item 1 in Figure 7.44. This will allow the shoes to stick to the tips of the three pistons. Figure 7.44 — Piston Pivot Shoes

Item

Name

1

Unloader/pressure regulator assembly

2

Washer

3


3. Place the piston pivot shoes onto the tips of the three pistons. The grease should hold the shoes in place.

3. Tighten the socket head cap screws to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.

99


4. Insert two (2) M6-1.0 x 45mm hex head bolts through mounting holes in the pump crankcase, 180° apart and at the locations shown in Figure 7.45. These are the two long “jacking” screws. Figure 7.45 — “Jacking” Bolt Locations

5. Lower the pump toward the engine adapter. Align the crankcase and engine adapter mounting holes and also position the three piston pivot shoes so that they engage the axial cam bearing race properly. 6. When you are sure the pump crankcase and piston pivot shoes are properly aligned and positioned, thread the two long hex head bolts (shown in Figure 7.45) into the engine adapter mounting holes. Turn the two screws alternately to compress the piston springs and pull the pump crankcase against the engine adapter. 7. Install four (4) M6-1.0 socket head cap screws through the mounting holes of the pump crankcase and thread them into the mounting holes of the engine adapter. Snug the four cap screws. 8. Remove the two (2) “jacking” hex head bolts and replace them with the two (2) remaining M6-1.0 socket head cap screws. 9. When all six (6) socket head cap screws are snugged down, tighten them to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.

100


Oil Fill Figure 7.46 depicts an early model pump and shows the drain plug (item 2) and the sight gauge (item 3). Figure 7.46 — Pump Oil Fill Location

1. On units so equipped, install the glass sight gauge in its proper position on the side of the pump. Tighten the sight gauge to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter. 2. On units so equipped, install the 3/8” NPT oil drain plug in its proper location. Tighten the oil drain plug to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter. 3. Insert a funnel into the Oil Fill/Breather cap threaded opening at top of the pump crankcase. Add the amount and type of oil recommended in the table in Part 2 of the Common Pump Components section, earlier in this manual. On units so equipped, the oil level should reach the center of the sight gauge. 4. When pump has been properly serviced with the recommended oil, install and tighten the Oil Fill/Breather cap to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter. 5. If so equipped, install the 1/8” NPT pipe plug into its threaded opening on the pump head. Tighten the plug to the torque value specified in the Torque Chart, found on Figure 7.2 (Exploded View) at the beginning of this chapter.

Item

Name

1

Oil fill - breather cap

2*

Drain plug

3*

Sight gauge

* Items not used in current models

101



Possible Cause

Corrective Action

1. Water leakage at mating flanges.



b. Damaged head.

b. Replace head.



a. Chemical injection fitting improperly torqued.

a. Torque fitting.

b.Check ball missing.

b. Replace check ball and spring.

c. Check ball stuck.

c. Remove, clean and replace fitting, ball and spring.



b. Defective head gasket.

b. Install good head gasket.

c. Damaged head.

c. Replace head.

d. Missing or damaged o-rings and backup rings.

d. Install new o-rings and backup rings.

a. Connector not properly seated.




a. Defective or missing head gasket.

a. Install new head gasket.

b. Head bolts improperly torqued.

b. Torque head bolts properly.

c. Porosity in spacer plate.

c. Replace spacer plate.

a. Thermal bypass piston missing or defective.

a. Install thermal bypass piston.

b. Bad or missing thermal bypass piston spring.

b. Install new spring.

c. Bad o-ring on thermal bypass piston.

c. Install new o-ring.

d. Low pressure water seals leaking.

d. Install new low pressure seals.

e. Defective or missing o-rings on spacer plate truss head screws.

e. Install new o-rings on screws.

f. Spacer plate screws not tight.

f.Tighten to correct torque.

a. Defective or missing engine adapter o-ring or gasket.

a. Install new o-ring or gasket.

b. Engine adapter cap screws not tightened properly.


2. Water leakage from chemical

injector.

3. Water leakage between pump head

and spacer plate.

4. Water leaks from high pressure out

connector.

5. Water leaking out of head bolts.

6. Water leaking out behind spacer

plate.

7. Oil leak between engine and engine adapter.

102



Possible Cause

Corrective Action

8. Oil leak between engine adapter and pump crankcase.





9. Oil leak between pump crankcase and spacer plate.

a. Missing or bad low pressure seals.

a. Install new seals.

b. Missing or bad piston oil seal.

b. Install new oil seals.

c. Cracks in casting.

c. Replace cracked casting.

a. Nozzle is set to low pressure mode. 10. Pump does not produce pressure, exhibits erratic pressure, chatters or has b. Incorrect spray nozzle is used. a low water volume. c. Spray nozzle is obstructed.


a. Reset nozzle to high pressure. b. Replace with correct nozzle. c. Clear obstruction from nozzle.


d. Clear inlet.






g. Clean strainer.




i. Disassemble and repair pump.

j. Unloader-regulator valve set wrong.

j. Set valve to high pressure.

k. Obstructed nozzle.

k. Clear nozzle of obstructions.

l. Obstructed chemical injection system.

l. Remove, clean and replace chemical injection components.







103


104

Portable Pressure Washer Familiarization and Troubleshooting Guide Glossary

GLOSSARY The following are definitions for terms commonly used in the pressure washer industry. Ampere – a unit of measure for current draw

FAIP – a pressure washer pump manufacturer

Annovi Reverberi – a pressure washer pump manufacturer

FH – same as ‘flathead’ pump, now known as a medium frame pump

Arrestor – see ‘spark arrestor’Assy – same as ‘assembly’ or group of parts

Foamer – a device used to inject soap, wax, or other additives into a stream of low pressure water

Awg – a unit of measure, relating a wire diameter in terms of American Wire Gauge

General – a pressure washer pump manufacturer GFCI – same as ‘ground fault circuit interrupter’, a device used to almost instantly cut off circuit power when an improper grounding condition is sensed

Axial cam - a device (cam) used to transform the rotary motion of the motor crankshaft into the reciprocating motion of a pump’s pistons; also known as a ‘wobble plate’

GN – a trade name for a certain type of Generac-Nagano internal combustion engine, such as GN-220, etc.

Backflushing – a method of reversing water flow through a system in order to flush out any blockages or impurities

GPM – a unit of measure for water flow; same as ‘gallons per minute’

Backwashing – same as backflushing

GPW – same as ‘Generac pressure washer’ pump, now known as a large frame pump

Belleville – a trade name for a certain type of domed steel washer BHCS – same as ‘button head cap screw’, a type of fastener

Helpline – special telephone answering service that can assist Generac owners having operational questions

BSP - same as “British Straight Pipe”, a type of pipe thread

HHCS - same as ‘hex head cap screw’; a type of fastener

Centura – a trade name for a certain type of Tecumseh internal combustion engine

HM – same as ‘hour meter’, a device used to record the elapsed time a device is operated

Connector – a device used to make an electrical connection between two or more circuit wires; a device used to attach water hoses, high pressure hoses, and so forth

HP – same as ‘horsepower’, a unit of measure for work Intek - a trade name for a certain type of Briggs & Stratton internal combustion engine

Contaminants – chemicals or particles of inappropriate matter mixed with known good materials

Keyway – a special slot cut into an engine shaft that is intended to mate with a matching key in a pump; permits maximum transfer of power from engine to pump

Couplings – devices used to make a mechanical connection between two rotating shafts or threaded pipes, etc.

Lavor Wash – a pressure washer pump manufacturer

CSA - characters which signify that the labeled device complies with applicable regulations promoted by the Canadian Standards Association

Loctite – trade name for a brand of assembly adhesive

Lbs – same as ‘pounds’ Ml – same as ‘milliliter’, a unit of measure for volume

CST – signifies Central Standard Time

Newton – a unit of measure for force

Degreaser – a chemical used to remove grease or similar petroleum-based products from a surface or object

NFPA – same as ‘National Fire Prevention Association’

Dia – same as ‘diameter’

NPT – same as ‘national pipe taper’, a designator applied to a specific type of pipe threads

Dipstick – a device used to indicate the level (amount) of oil in a pump/engine crankcase

NSP – same as ‘non-service part’; the entire assembly must be replaced as a unit

EE – same as ‘economy electric’ pump, now known as a small frame pump powered by an electric motor

OHV – same as ‘overhead valve’, an improved way to control exhaust and intake valves on internal combustion engines

EG – same as ‘economy gas’ pump, now known as a small frame pump powered by a gasoline engine Eng – stands for ‘engine’ or ‘engineering’

OHVI – an industrial, more durable version of the ohv engine 105

Portable Pressure Washer Familiarization and Troubleshooting Guide Glossary

Overchoking – a condition where the engine is being deprived of intake air while being flooded with fuel Overflush – a mechanical condition where one surface is slightly higher than its surrounding surface Overspraying – a condition where a substance (paint, high pressure atomized water, etc.) is broadcast outside of its intended region Overtighten – a condition where a fastener or other securing device is more than fully engaged, causing possible damage to its associated components or difficulty in removal Parback – a trade name for a type of fluid seal device Permabond – a trade name for a type of industrial adhesive Poppet – a type of valve used to relieve pressure

Turbo wand/nozzle – a device used to increase the effectiveness of high pressure water when directed against a surface UL – same as ‘Underwriters Laboratory’, a safety and performance testing service Unchamfered – indicates that sharp edges are not machined with a chamfer Unloader - a device used to reduce the water pressure within a pressure washer pump whenever the spray flow is blocked. Vanguard - a trade name for a certain type of Briggs & Stratton internal combustion engine Vaseline – a trade name for a type of petroleum jelly Wireform – a type of hose or accessory hanger formed from heavy wire and attached to pressure washers

PSI - a unit of pressure; same as ‘pounds per square inch’ Purge - a method of eliminating air from a pressure washer so that starting the engine is easier PW – same as ‘pressure washer’ QPQ – same as ‘quench purge quench’, a heat treating process designed to case-harden pressure washer pistons Quantum - a trade name for a certain type of Briggs & Stratton internal combustion engine Quattro - a trade name for a certain type of Briggs & Stratton internal combustion engine RPM – same as ‘revolutions per minute’ SAE – same as ‘Society of Automotive Engineers’ SF – designates a specific grade of automotive oil SG – same as ‘sf’ SH – same as ‘sf’ Side valve - a type of internal combustion engine that uses a conventional “L” type cylinder head with intake and exhaust valves on the side SHCS – same as ‘socket head cap screw’; a type of fastener Spark Arrestor – a device or screen that prevents the emission of sparks from an engine’s exhaust Sprint - a trade name for a certain type of Briggs & Stratton internal combustion engine SRV – same as ‘service’, used to designate a service part Thermal relief - a technique used to reduce the build-up of high temperature water with a pressure washer pump caused when the spray gun trigger is closed. 106

B3277GS Pressure Washer Pumps by Generac

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