Vmax surging at higher RPM

[Cphil]

I have a carbed Vmax 150 (V150TLRY). It seems to be starving for
fuel or has a vacuum leak at higher speed/rpm. It will surge and slow
itself down when I try to go WOT. So far every thread I’ve read points
to replacing both fuel pumps. I have a clean pick-up tube, new filter
assembly, new spark plugs and I’ve replaced all the fuel lines and fittings
all the way from the pick-up tube up to the carburetors. This boat sat
a lot (usually with gas in the tank) and I just bought it recently. I
haven’t had it out since replacing what I mentioned but I was hoping
someone hear could lend some advice as far as what else to look for
while I wait on getting my new fuel pumps. Thanks guys!!

[Amistad Tackle]

It is likely the fuel pumps. Common problem.

[Cphil]

Fingers crossed. Thanks

[Bass Junkie]

Fuel pump diaphragms.

[4fishlips]

Yes the fuel pump diaphragms the ethanol gas loves them.

[Cphil]

Yes the fuel pump diaphragms the ethanol gas loves them.

Thanks guys. Finished putting on all new fuel lines and hose clamps and the two new pumps
today. Won’t hit the lake for a hard run until next week

[bassinman215]

Another thing to check is the anti-siphon valve on the fuel tank. That was the issue on mine. Mine would get on plane and promptly lose speed. Tried cleaning carbs and replacing the fuel pumps before I figured out it was the anti-siphon valve.