Fuel Pump problem?

[dangib]

I have a 2002 Mercury O.B. 40 HP, 4 stroke motor and when I take the boat out, it starts up fine and idles fine, but when I put it full throttle, the engine seems to "hestitate". It runs fine for the first few minutes and then it has the feeling as if your car was running out of gas. When I pump the fuel bulb the boat runs good again, but then "hesitates" again after a few minutes. I continually have to pump the bulb to make it run smoothly. I replaced the fuel line and bulb and fuel tank and I also cleaned the fuel filter. The problem still exists. Could this be the fuel pump??? Also, when I am trolling or running at a lower speed, I dont have this problem and it runs fine. If anyone has any suggestion, Id appreciate the response. Thank you.

 

[rodbolt]

Re: Fuel Pump problem?

sounds like a bad pump or a clogged filter. could be an airleak. usually an air leak on the pressure side of the fuel primer will be a fuel leak when ya pump the bulb.all the fuel primer does is fill the pump,lines and fuel bowls before starting. after that the engine pump takes over. by pumping the bulb your bypassing the fuel pump. your on the right track. keep looking.