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Losing Fuel Prime on Yamaha 1997 150hp

tperk100

tperk100

Member
Previous to owning this 1997 2 stroke Yamaha 150, I owned 4 other 2 strokes. My experience has always been that it was necessary to hand pump the primer bulb until it became so hard/stiff that you could not really pump it up any more.

On this engine the bulb never gets "hard." I pump it up until I feel only a very small amount of resistance and the engine starts fine. HOWEVER, after being on the water fishing for a couple of hours without running the engine, and then trying to re-start, sometimes I have to pump the bulb up again.

Maybe I am losing prime? Or is it something else? How do I troubleshoot this? Why does the bulb not became "hard" when I pump it?

Don't know if this has anything to do with it, but I keep the boat in my garage, and there is usually at least a little odor of gasoline present.

Thanks for any help.
 
Re: Losing Fuel Prime on Yamaha

You either have a leaking fuel pump diaphragm or a leaking float valve in a carburetor ( if equipped with carburetors )----------------Bulbs are nothing but a " manual fuel pump " and being able to pump a bit of fuel when a motor is running is NORMAL.
 
Re: Losing Fuel Prime on Yamaha

if it has the little fuel filter on the motor , check the bowl, they like to loosin up from vibration, buy a cheap in-line put it on the OUTSIDE of the motor take the other off and throw it in a wooded direction....
 
if you have water separator filter then open it and check is there any dirt inside, if you don`t have filter then open the valve and check inside is there
any particle stuck off in front of the valve. or exchange the valve with good one and check.
 
Re: Losing Fuel Prime on Yamaha

racerone said:
You either have a leaking fuel pump diaphragm or a leaking float valve in a carburetor ( if equipped with carburetors )----------------Bulbs are nothing but a " manual fuel pump " and being able to pump a bit of fuel when a motor is running is NORMAL.
Click to expand...

This is the one you will want to check first, the leaking fuel pump diaphragm.
 
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