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2 cylinders rough and sputters, 1 cylinder fine

Biksco

Biksco

New member
I've got a Johnson 60 hp 1982 2-cylinder J60ELCNM outboard.


The engine runs rough and sputters with both spark plugs connected. If I disconnect the top spark plug, the engine runs smooth on the bottom cylinder only.


Is this an electrical or mechanical problem? What should I be looking for?
 
Did a compression test - both cylinders fine. The engine RUNS (with both cylinders), but they don't want to behave together. (or at least one doesn't)
 
Compression: Bottom cylinder as 125 - top cylinder was 115. Spark plugs are brand new - gap checked. The top one has the issue.
 
Some will argue.-----Those compression numbers are very low.------I have checked more than one of those motors at 140 / 145 PSI compression.----Time to remove the cylinder head for an inspection of cylinder walls !!
 
Biksco said:
Compression: Bottom cylinder as 125 - top cylinder was 115. Spark plugs are brand new - gap checked. The top one has the issue.
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I have 2 1982 models. Just got done with refreshing one. I agree compression seems low, but are within 15 psi of eachother so thats good. One of my motors reads 147 and 150 psi, the other was sitting for years and read 145 and over 160psi for cyl #1! Should even out once run a bit. Pop off the head before doing anything to be sure you arent wasting time!
But your problem sounds like either a bad ground at the coils or the tan temp wire has shuffled its way over to the plugs/leads. be sure to zip tie it as far away from the plug wires as possible. as per the manual, jump wires between the 2 primary orange coil wires (assuming the old style coils are still on it) of the 3 point connector going into the power pack and see if the voltage jumps around when running with DVA connected to the meter. let us know what you find.
 
Hey Guys! Thanks for the answers! I'm doing this for my non-computer savy neighbor. I shot this video showing & explaining what's going on:


But your problem sounds like either a bad ground at the coils
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Revenge22: Interesting! My neighbor complained (in the video) of getting zapped when pulling out the plug! We'll take a careful look at that!
 
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