Yamaha Prov 150 fuel issue - real simple??

[Cantcatchathing]

My 150 ProV sat for a year. Started up like a champ, ran great in drive way w/ muffs on. Out on lake, it bogs down above 2300 rpm, and will intermittenty surge if I play w/ the throttle, but only for 1-2 seconds, and then back to bog condition. Reading some of these other (very informative BTW) threads sounds like I should target pump diaphragms before screwing around w/ carbs. But also noticing bulb does will not pump up to a firm condition. It pumps fuel adequately to get engine started, but never gets hard. Is there an easy way to isolate possible air leaks into fuel supply that is upstream (btwn pumps and tank) of pumps, or should I investigate other issues first?

 

[Redneck Yacht Club]

Re: Yamaha Prov 150 fuel issue - real simple??

1 year of old fuel sitting in a carbs.............Carb job needed
New fuel will not work either, old fuel has seprated and is yellow varish.
Also what year is it? They did have some problems with thier fuel pumps screws in there.I think there $40 bucks a piece. Cheap!

 

[Ray Neudecker]

Re: Yamaha Prov 150 fuel issue - real simple??

Likely hood of carb and fuel pump problems after sitting is great. Bulb not getting firm is often a symptom of a fuel pump leaking into the block.
Replacing the fuel pumps and rebuilding the carbs would be the logical course as well as being sure the fuel is fresh and filters changed.