1986 Evinrude 150 hp skipping

randyray41

Petty Officer 2nd Class
Joined
May 31, 2011
Messages
123
Had boat out yesterday, was running fine until it developed a skip. I checked plugs and found that the #1 cylinder plus was shiny clean. The other plugs were the usual brownish black color. The plugs were brand new. I changed the clean plug and tried it again. Once again, after a few minutes of running it started skipping.

How do I diagnose this issue? Plug wire? Coil? or power pack going bad.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,129
Re: 1986 Evinrude 150 hp skipping

Compression test it and check for spark on that cylinder.
A clean plug could have a head leak.
If you have time to spare see if the plug gets rust on it while still in the engine for a couple of days after you have used it
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1986 Evinrude 150 hp skipping

Water in the cyl can kill the spark and give the plugs a shiny clean appearance. It may also affect the color of the face of the piston. You may want to pull all 6 plugs and check the color of the #1 piston face vs the other 5. Also possible you are just dropping spark on #1. A good test would be to swap #1 coil with another nearby, then see what happens. Weak ignition components tend to fail once they heat up to normal operating temps. May run fine when cold, the start to fail as the engine warms up.
 
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