Yamaha F115 2003 problems

[Hookedonsnook]

My engine just started having problems the last trip out. It started out fine, but towards the end of the trip i noticed it was acting weird. It started up just fine, but it took a while to get up on plane and i had to "pump" the throttle to get it up. also once i got it up on a plane it would not hit max RPMs. But if i backed down on the trottle a little and pushed it back up it would get up to the normal max rpm range, but would only stay there for maybe 5 seconds and then go back down. The engine just sounded diffent then it ussualy does. i'm pretty good with 2 strokes, but don't know much about 4 strokes.... any idea what it could be?

 

[rodbolt]

Re: Yamaha F115 2003 problems

same as any motor.
your describing a lack of fuel in one or more cylinders.
when was the last time the VST filter was cleaned or replaced?
fuel rail pressure is critical on any EFI engine.
check rail presure at the problem RPM.