stalling/hard starting/rpm loss, 99 s250turx yamaha

[GB250]

this can't be happening! engine stalling, found leaking o ring on VST tank, replaced o ring, engine still stalling, found it loading up on fuel, with plugs removed, cranking showed fuel shooting out of #1&#2, replaced all three mechnical fuel pumps, two of the pumps had ripped back diaphrams, engine started fine and no stalling, no fuel leaks at the dock, go out for a ride and engine will not go over 3,000 rpm, it will not stall, but loses rpms. Any advice would be appreciated, also what should be base idle be? can you tell shaft length from the TURX, considering repower, PS tuseday I checked fuel pressure 35-38 psi at base idle,, Thanks GB

[Hamfisted]

Its a 30" shaft motor. Did you put a new set of plugs in it? Or what color are the plugs when you pull 'em out? If it was eating a lot of raw gas before this fix, you might have fouled the O2 sensor and it needs cleaning as well.


http://www.boatsetup.com/O2sensor.pdf


Mike

[GB250]

Thanks Mike, I cleaned plugs before replacing simply because they were new to begin with, But I will replace them. o2 sensor had not been cleaned since new, do you think since it was cleaned a few days that now its fouled and that can cause no rpms over 3,000? What syptoms would defective fuel injectors give? Thanks for all your advice


Guy

[Hamfisted]

Guy is the fuel primer bulb collapsing when this power loss is happening? You checked the Racor filter? Throttle position sensor?


Mike