Rough Idle?

[garywayner]

I have a 1985 115 Evinrude and when it?s idling the RPMs are jumping around by about 100, is that too much?

 

[ob]

Re: Rough Idle?

Is it the tach that is fluctuating or can you hear the engine rpms changing as well?Did this symptom just recently occur and does the engine run fine otherwise?How about the plugs?Are they the recommended Champion plugs gapped properly?

 

[tashasdaddy]

Re: Rough Idle?

Have you check spark, when idleing. is throttle plate staying closed?

 

[garywayner]

Re: Rough Idle?

This is on the tach meter and the motor runs fine when above 1500-2000 RPMs. The plugs are new Bombardier installed at the service shop about two months ago, which I assume are correct for this engine.

What would be great is if someone could post a video clip of one of these engines running at idle? Anyway, some more thoughts would be great.

 

[Pony]

Re: Rough Idle?

25hp Johnson

There is a link to a video of my 88' 25hp running last spring at idle. Obviosly not as large as your engine..........but the idle should "sound" the same just a bit deeper. At least I feel as though my motor was idleing pretty well.....tough to tell on video sound.

I dont think the rpms will really ever sound perfect on muffs since there is not consistant backpressure........

 

[Kevin W]

Re: Rough Idle?

maybe a silly question but how old id the gas?
gas ages much faster than it did years ago.
since its early in the season maybe its last years gas? if so was a stabalizer added? if not maybe its only just old gas.
I am currently using October gas that had stabalizer in it and mine is idling a little rough too.
I will wait till all the older gas is gone b4 i worry.