Motor Stalling/Primer Bulb?

J

Johnny Stugots

Cadet
Joined
Apr 10, 2007
Messages
27
I took the boat out for a spin yesterday. When I proceed to go full throttle, the rubber primer bulb tightens up, gets flat. My vent was also open on my fuel tank. Should I buy a new primer bulb or is there air getting into the fuel line? What do you guys think?

40 hp Yamaha four stroke.

Thank you
 
L

lakensea

Chief Petty Officer
Joined
Jan 30, 2002
Messages
542
Re: Motor Stalling/Primer Bulb?

Either the primer bulb has a stuck check valve or you have an obstruction between the primer bulb and tank (kinked or collapsed fuel line). From the way you said the vent was open, I assume you have a portable tank, so that would rule out the anti-siphon valve or obstruction in the tank vent line. An air leak will not cause the bulb to go flat.
 
J

Johnny Stugots

Cadet
Joined
Apr 10, 2007
Messages
27
Re: Motor Stalling/Primer Bulb?

The motor ran totally fine at half speed. This happened at full throttle, do you still think there would be a kink in the fuel line?
 
M

mattttt25

Commander
Joined
Sep 29, 2002
Messages
2,661
Re: Motor Stalling/Primer Bulb?

i've been told that many times an aftermarket bulb will actually cause problems, and that their not worth the money. i'd replace the bulb with an oem part and see if that corrects the problem.
 
Y

yamamarinetech40

Petty Officer 1st Class
Joined
Dec 17, 2006
Messages
328
Re: Motor Stalling/Primer Bulb?

A vacuum gauge just in front of the engine's fuel filter with a piece of clear vinyl hose(avail. @ hardware store, boat store, etc.) put inline between tank and gauge will tell you all....should see no or VERY few bubbles and vacuum should be about 2 inches or less at idle and always below 5 inches @ WOT....and don't assume if you get the good reading @ idle you will also pass @ WOT....seems like very few people do this simple test and it eliminates the 'may be' part....
 
S

spec and red

Cadet
Joined
Apr 22, 2007
Messages
9
Re: Motor Stalling/Primer Bulb?

Have 4-stroke Yamaha 115 tank in deck, ran great friday and saturday, but come sunday ran about two miles and motor seem to be running out of fuel have 42 gal. tank. plenty of fuel, bulb just went flat too. As long as I smashed the bulb over and over it ran then died out again. Could it be the bulb or fuel line? Just bought the boat, now cant seem to keep it running.
 
You must log in or register to reply here.
Top