2002 yamaha 250hp ox66 shuts down at full throttle

[mikep6]

when running at full throttle for a while it will shut down like you turned the switch off after you stop starts back up and runs good untill full throttle for while will run like a champ all day around 55mph but around 60 to 73mph for any period of time like you turned the switch off.smokes alot when youre at idel and uses a lot of oil thanks

 

[cousinabe]

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

when was the last time you cleaned your VST?
cleaned AND tested your O2 sensor?

 

[rodbolt]

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

I would also check/replace all three lift pumps and clean the VST filter.
your describing a classic loss of fuel rail pressure and a classic case of a ruptured lift pump diaphram.
on the oil,check the link on the oil pump control rod, if it breaks the pump goes wide open. but that wont shut it down.

 

[mikep6]

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

i have never cleand them is the 02 sensor on the right side around the 2nd cyld down and the vst is that the screen on the fuel pump inside the meattle can thanks for all the help i will try to clean tommorow afternoon thanks again