Mercury Mariner Download 1965 1989 Service Manual 45 to 115 Hp Outboard

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4- 10

FUEL

t h e fuel line, t h e fuel pickup in t h e tank, t h e f u e l f i i t e r , anti-siphon valve, t h e f u e l tank vent, and excessive foreign m a t t e r in t h e f u e l tank, and loose fuel f i t t i n g s sucking a i r into t h e system. Improper size fuel f i t t i n g s can also r e s t r i c t fuel flow. On most installations, t h e f u e l line is provided with quick-disconnect f i t t i n g s at t h e tank and at t h e engine. If t h e r e is reason t o believe t h e problem i s at t h e quick-disconnects, t h e hose ends should be replaced as a n assembly. For a small additional expense, t h e e n t i r e fuel line can b e replaced, thus eliminating t h i s a r e a as a problem source f o r many f u t u r e seasons. T h e primer squeeze bulb can b e replaced in a s h o r t time. F i r s t , c u t t h e hose line as close t o t h e old bulb a s possible. Slide a small c l a m p over t h e end of t h e fuel line from t h e tank. Next, install t h e SMALL e n d of t h e c h e c k valve assembly i n t o this side of t h e fuel line. The check valve always goes towards t h e fuel tank. P l a c e a l a r g e c l a m p over t h e end of t h e check valve assembly. Use Primer Bulb Adhesive when t h e connections a r e made. Tighten t h e clamps. Rep e a t t h e procedure with t h e o t h e r side of t h e bulb assembly and t h e line leading t o t h e engine.

If the engine will M ,make every attempt t o regain satisfactory performance by making carburetor adjustments, before assuming the carburetor is at fault.

ROUGH ENGINE IDLE If a n engine does n o t idle smoothly, t h e most reasonable approach t o t h e problem i s t o perform a tune-up t o e l i m i n a t e such d e f e c t i v e points; f a u l t y spark a r e a s as: plugs; and timing o u t of adjustment. O t h e r problems t h a t can prevent a n engine from running smoothly include: An a i r leak in t h e i n t a k e manifold; uneven compression between t h e cylinders; and sticky o r broken reeds. Of course any problem in t h e c a r b u r e t o r a f f e c t i n g t h e a i r f f u e l mixture will also prev e n t t h e engine f r o m operating smoothly at idle speed. These problems usually include: Too high a fuel level in t h e bowl; a heavy float; leaking needle valve and seat; defective a u t o m a t i c choke; and improper adjustm e n t s f o r idle mixture o r idle speed. EXCESSIVE FUEL CONSUMPTION Excessive fuel consumption can be the result of any one of t h r e e conditions, o r a combination of all three. 1- Inefficient engine operation. 2- Faulty condition of t h e hull, including excessive marine growth. 3- Poor boating habits of the operator. If t h e fuel consumption suddenly increase s over what could be considered normal, t h e n t h e cause can probably be a t t r i b u t e d t o t h e engine or boat and not t h e operator. Marine growth on t h e hull c a n have a very marked e f f e c t on b o a t performance. This is why sail boats always t r y t o have a haul-out a s close t o race t i m e as possible. While you a r e checking t h e bottom t a k e

usually the result of leaving the boat in the water for long periods of time. The time for such growth t o develop is drastically shortened in salt water and in warm temperatures. Such a condition seriously hinders proper performance.


ENRICHEMR SYSTEM n o t e of t h e propeller condition. A bent blade or o t h e r d a m a g e will definitely c a u s e poor b o a t p e r f o r m a n c e . If t h e hull a n d propeller a r e in good s h a p e , t h e n c h e c k t h e f u e l s y s t e m f o r possible leaks. C h e c k t h e line b e t w e e n t h e f u e l pump and t h e c a r b u r e t o r while t h e e n g i n e i s running and t h e line b e t w e e n t h e f u e l t a n k and t h e pump when t h e e n g i n e is n o t running. A l e a k b e t w e e n t h e t a n k a n d t h e p u m p m a n y t i m e s will not a p p e a r when t h e e n g i n e i s o p e r a t i n g , b e c a u s e t h e s u c t i o n c r e a t e d by t h e pump drawing f u e l will n o t a l l o w t h e f u e l t o leak. O n c e t h e e n g i n e is t u r n e d off a n d t h e s u c t i o n no longer e x i s t s , f u e l m a y begin t o leak. If a minor tune- up h a s b e e n p e r f o r m e d and t h e s p a r k plugs, points, and t i m i n g a r e properly adjusted, t h e n t h e problem m o s t likely is in t h e c a r b u r e t o r and a n overhaul i s i n order. C h e c k t h e n e e d l e valve and seat f o r leaking. In a n e f f o r t t o c o n s e r v e f u e l , u s e e x t r a c a r e when m a k i n g a n y a d j u s t m e n t s a f f e c t i n g t h e f u e l consumption, such as t h e f l o a t level o r a u t o m a t i c choke.

4-1 1

vice t o b e a s a f e t y item, but more o f t e n t h a n n o t , t h e valve m a y c a u s e m o r e probl e m s in t h e f u e l delivery s y s t e m t h a n t h e y solve. If t h e valve b e c o m e s t h e l e a s t b i t clogg e d with d e b r i s o r a t o o s m a l l v a l v e i s installed in t h e f u e l line, o r t h e s p r i n g i s t o o s t o u t , a pressure d r o p m a y d e v e l o p f r o m o n e side of t h e valve t o t h e o t h e r . A p r e s s u r e d r o p a c r o s s t h e anti- syphon valve c a n c a u s e poor powerhead p e r f o r m a n c e a n d possible damage.

ENGINE SURGE

A d e f e c t i v e or poorly o p e r a t i n g a n t i syphon valve m a y c a u s e o n e o r m o r e of t h e following problems: I n a d e q u a t e f u e l p u m p pressure. Loss of power at t h e powerhead. P o w e r h e a d s u r g e a t high s p e e d rpm. Piston d o m e erosion due t o preignition o r detonation. P o o r powerhead p e r f o r m a n c e during acc e l e r a t i o n -- u n i t f a l t e r s o r c u t s o u t c o m pletely. P o w e r h e a d f a i l s t o o p e r a t e smoothly -r u n s "rough". Powerhead cannot be started.

If t h e e n g i n e o p e r a t e s as if t h e load on t h e b o a t is being c o n s t a n t l y i n c r e a s e d a n d d e c r e a s e d , e v e n though a n a t t e m p t i s being m a d e t o hold a c o n s t a n t e n g i n e s p e e d , t h e problem c a n m o s t likely be a t t r i b u t e d t o t h e fuel pump, o r a r e s t r i c t i o n in t h e f u e l l i n e between the tank and t h e carburetor. O p e r a t i o n a l description a n d s e r v i c e proc e d u r e s f o r t h e f u e l p u m p a r e given in S e c t i o n 4- 1 1.

Checking Anti-Syphon Valve If troubleshooting should i n d i c a t e t h e anti- syphon v a l v e is at f a u l t , a t t e m p t t o o p e r a t e t h e p o w e r h e a d with a s e p a r a t e f u e l source. In o t h e r words, t h e valve i s physic a l l y bypassed. If t h e valve proves t o be t h e s o u r c e of t h e p r o b l e m , e i t h e r r e m o v e t h e valve f r o m t h e fuel line or r e p l a c e t h e v a l v e with a solenoid o p e r a t e d f u e l s h u t o f f valve.

ANTI-SYPHON VALVE

4-4 ENRICHENER SYSTEM

WORDS ON REQUIREMENT A t press t i m e , in t h e United S t a t e s , t h e r e is no g o v e r n m e n t a l regulation requiri n g a n o u t b o a r d m o t o r t o be equipped with a n anti- syphon valve. H o w e v e r , b o a t s c o m plying with t h e Boating Industry Association (MA) C e r t i f i c a t i o n P r o g r a m , vessels w i t h p e r m a n e n t l y installed f u e l t a n k s a r e require d t o h a v e a n anti- syphon valve. B e a r i n mind, t h e BIA sets a s t a n d a r d which i s not s u b j e c t t o e n f o r c e m e n t by a n y g o v e r n m e n t agency.

S o m e l a t e m o d e l powerheads c o v e r e d i n this m a n u a l a r e e q u i p p e d with a n e n r i c h e n e r s y s t e m , r e p l a c i n g t h e t r a d i t i o n a l c h o k e system. An e l e c t r i c a l l y o p e r a t e d e n r i c h e n e r valve m o u n t e d on t h e p o r t side of t h e powe r h e a d , as shown in t h e accornpanying illust r a t i o n , is supplied w i t h f u e l via a f u e l l i n e f r o m t h e f l o a t bowl of t h e t o p (No. I ) c a r b u retor.

An anti- syphon v a l v e is considered a n " A f t e r Market" i t e m , n o t installed by t h e f a c t o r y . Many people consider such a de-

When t h e ignition key i s r o t a t e d t o t h e ON position a n d pushed inward t o s t a r t a c o l d powerhead, t h e e n r i c h e n e r s y s t e m is e n e r g i z e d . File1 is t h e n f e d t o a l l c y l i n d e r s through s h o r t hoses and f i t t i n g s at t h e in-

















































































































































































































































































































































































































































Mercury Mariner Download 1965 1989 Service Manual 45 to 115 Hp Outboard

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