Yamaha F-150 Idles Rough

[jmiskovs]

This is a 2004 model and the engine runs perfectly at all speeds except idle. Motor starts right up each time, but idles rough. No smoke or smell of rich fuel, just a constant change in idle speed.

Plugs have been changed along with the fuel filter and water seperator. The engine started doing this last year.

Anyone have a solution?

Thanks.

 

[rodbolt]

Re: Yamaha F-150 Idles Rough

this is an easy one, test the cylinder leakage, if the leakdown rate is acceptable place it on the laptop or diagnostic test lamp. if no codes are found clean the VST and injector filters and use the techmate to insure the throttle shutters are prioperly set.
odds are high you will find the issue.