94 Force 15. Fuel coming out of primer bulb hose attached to carby

haz_hart

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Dec 11, 2009
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Hi my names Harry,
I'm working on this 1994 Force 15hp outboard motor, has had issues starting. Recently cleaned fuel pump, filter, diaphram and carby they appear to be in good condition. Fuel is surging out of primer bulb and the motor wont idle so I took the bulb of and put my finger over the hole and it stalls. I relies the fuel bulb attached to the tank is one way but this bulb appears to be two way. Also blowing alot of smoke (fuels clean). Is this because its running rich, tried to lean out slighly, prob persisted! Any suggestions. :
 

CharlieB

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Apr 10, 2007
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Re: 94 Force 15. Fuel coming out of primer bulb hose attached to carby

The primer bulb is designed with TWO check valves, inlet and outlet, when the check valve fail all check valve function is imposed on the fuel pump inlet valve, it is not designed to handle that much load and it will shorten its service life. Replace the primer bulb.

Smoke is normal on a 2 stroke at a 50 to 1 mix. But poor spark, fouling spark plug, overly rich fuel/oil mix, or an overly rich carb, idle mixture, can cause a lot more smoke.

If a motor has been slightly over rich for some time the exhaust passage will accumulate soot and oil causing the motor to drip black nastiness in the driveway when parked.

Check/change sprak plugs, test spark on all cyl's.

Test compression to be sure there are no mechanical problems developing.

Once you are satisfied that the ignition system is fine then check/readjust idle mixture while on the water at idle in forward gear. Set mixture screws to best idle in gear plus 1/8 turn, then test acceleration by rapidly opening the throttle from idle to WOT, the boat should move out smartly with no hesitation, cough, or bog. If any of these then the idle mix is still too lean, add another 1/16 turn OUT to richen, retest acceleration from idle. Repeat if needed till all traces of bog or hesitation are gone.
 

haz_hart

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Dec 11, 2009
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Re: 94 Force 15. Fuel coming out of primer bulb hose attached to carby

Thanks CharlieB I'll give it a shot. Once I get hold of new primer bulb I'll keep you posted with results. I'll also try and play around with the mixture and see how that goes.

Another question:-

Does the bulb create any fuel pressure and would it affect the fuel flow?
 

CharlieB

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Re: 94 Force 15. Fuel coming out of primer bulb hose attached to carby

The only time the bulb makes any pressure or flow is while you are squeezing it, the rest of the time it simple functions as a check valve to prevent any fuel flow BACKWARDS between the pulses of the fuel pump.
 

haz_hart

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Re: 94 Force 15. Fuel coming out of primer bulb hose attached to carby

I've had a break through, the fuel bowl can be adjusted to vary the quantity of fuel the float allows. I was playing around and notice how to make it leaner which the stopped fuel comming out of the bulb.
The only issue I'm having now is finding the equalibrium so it doesnt hunt when its to lean and stall/ flood when it's to rich. Is anyone aware of the angle? Ive been inching it back and forth 5 degrees to try and find the right angle. It's been a bloody fiasco! lol
 

haz_hart

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Dec 11, 2009
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Re: 94 Force 15. Fuel coming out of primer bulb hose attached to carby

CharlieB this may well be one of the biggest bloppers you have seen. Hope you have a few laughs out of it anyway. I've definitely learned alot and thankyou for being informative. When I initially took the carby off to clean with compressed air I gave it to a partner to clean and when they reassemble it they put the float in upside increasing the height of fuel level hence causing it to run rich. After exhausting every possible scenario the problems finally resolved.

Cheers, kind regard Harry
 
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