1980 35hp Johnson won't idle

80johnson35hp

Recruit
Joined
Aug 13, 2010
Messages
5
New to working on outboards -great site. I have a 1980 Johnson 35hp with a Type IV carb. It will not idle a slow rpms. I have rebuild the carb and put in new plugs. The only way I can get it to idle smooth and stay running is to set the s/s needle to 1.5 turns out, and have the throttle open just to the point that the mechancial interlocks prevent it from shifting into and out of gear. Once in gear though, I can throttle up and it runs fine. I also noticed that when I open the throttle to get it to idle, the throttle plate does not need to open, I just need to advance the timing slighty (I think that is what is happening). Any thoughts?
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: 1980 35hp Johnson won't idle

Welcome to iboats.

Have you checked the timing?

Start with the basics and check compression and spark. The idle should be set to about 800 rpm under load and in gear. 1.5 turns out is a good starting point to start adjusting, follow the thread by Joe Reeves in the FAQ for fine tuning the slow speed needle.

Not likely your issue, but I recently discovered a 76 55hp that had idling issues. Took the face plate off the carb and discovered the top carb spitting fuel a good 12" from the mounting surface. Reeds were a mess.
 
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