2002 yamaha 250hp ox66 shuts down at full throttle

[mikep6]

it chugs 2 times then its like you turned the switch off.i have checked the vst and it and the fillter was clean,i took the 02 sensor off and didnt see any carbon build up i cleand it and put it back on.smokes alot when at ideal and i think it just fuald a plug it so orderd new plugs

 

[nickmo]

Re: 2002 yamaha 250hp ox66 shuts down at full throttle

I would have thought VST filter too. I don't think spark plugs would cause it to just shut down. It's usually a fuel related issue. It could be the low pressure pumps.

 

[cousinabe]

Re: 2002 yamaha 250hp ox66 shuts down at full throttle

check the vst pressure when problem occurs. possible lp pumps are not feeding vst at high rpms.
could also be water in your fuel too.