1986 Johnson 90 h.p. rough idle

rbickham

Cadet
Joined
Jul 9, 2006
Messages
23
I posted before about my rough idle problem. It has new rings and the carbs rebuilt. I took it back to the dealer i bought it from and complained, he said he would fix it for free! I picked it up today, didn`t get to talk to mechanic, but the counter person said it was ready to go. So i don`t know what they replaced. I took the cover off, looks like they replaced all four coils. I put it in the water today, it runs alot better and it was idling a little fast, so i backed it off. I noticed they had the idle adjust screw almost all the way in. Why would it have to be almost maxed out?
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: 1986 Johnson 90 h.p. rough idle

What is the idle rpm with the boat in the water - - ie. not on muffs? Should be around 700 rpm I think. Are the thermostats in? If not the engine will not get to operating temp and will idle rough.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,786
Re: 1986 Johnson 90 h.p. rough idle

And the 700 rpm is in F gear (engine loaded). d:)

Mark
 

rbickham

Cadet
Joined
Jul 9, 2006
Messages
23
Re: 1986 Johnson 90 h.p. rough idle

Texasmark said:
And the 700 rpm is in F gear (engine loaded). d:)

Mark

I will check RPM`s and thermostats.
Thank Youd:)
 
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