rough idle

[blanton]

I have a yamaha 2003 F25eshb that miss fires at an idle when you start it up runs fine then starts miss firing. I checked carb and fuel pump everything seems fine it had been running fine was on the water turned it off and when it was restarted it was missing above an idle runs fine any ideas ???

 

[Yamajoe]

Re: rough idle

Welcome to iBoats. Is the backfire a loud bang/pop or a sneeze? When you say you checked your carbs did ya tear it down or was this a visual inspection? did you set your air fuel mixture and idle as well as do carb sinchronisation with a Techmate or manometer? Sounds like your carbs may be running too lean, but in order for us to help you we need more info.

 

[blanton]

Re: rough idle

Thanks for your reply I guess it is more like a sneeze as it does not make any popping noise. I did tear the carb apart and it was spotless inside. When the engine comes to an idle it starts shaking like only one cylinder is firing will run like that for a few seconds then shut off if you kind of pump the throttle a little bit it will clear up above an idle will run fine.