2001 Volvo Penta 5.7 GSI bad sudden power hesitation

[imgettingmad]

I have a 2001 Volvo Penta 5.7 GSI, TBI and after boat gets warm at about 3000 RPMs engine spits/hesitates suddenly with a loud tap noise – most likely because all power shuts off suddenly at once. Under 3000 RPMs this does not happen. Boat runs kind of rough and rich. Things already done in effort to stop it: Spark Plugs, Cap/Rotor, External Coil, new fuel filter. Others have said it could be fuel pump – but boat takes throttle easily and there’s no whining noises from pumps. This is a giant headache and we want to enjoy our deck boat – does anyone have any suggestions? Thank you in advance!

-Shawn

 

[lode]

was your fuel stabilized properly at the end of last season?

did the boat set for awhile before this season?

check anti syphon valve?

check fuel line body to make sure it isn't collapsing under pump pressure?

What did your old fuel/water filter contents look like when you replaced it?

Does it happen only when you're planing at 3000 RPM's or does it do it when you're in neutral and rev the motor to 3000 RPMs?

There are many things it could be... need a little more info plz.

Sounds like water in your gas but that's a wild guess right now. That water in the bottom of the tank would increase at your tank pick up as it gathered at the corner of your tank when you're planing. Pull your fuel water seperator and pour it into a clear jar and look at the side view. the gas will be on the top... water on the bottom.

Hope it's disappeared and you're enjoying your boat!

Take care,
Lode