20HP misfiring

kyleenright

Recruit
Joined
Jun 6, 2022
Messages
3
I have a Johnson J20CRERC serial #G03590918 that is misfiring at slower speeds. I have 120 psi compression in both cylinders.
I'm new to this forum, I can attach a short video if its possible in the forum?
 

kyleenright

Recruit
Joined
Jun 6, 2022
Messages
3
I have a Johnson J20CRERC serial #G03590918 that is misfiring at slower speeds. I have 120 psi compression in both cylinders.
I'm new to this forum, I can attach a short video if its possible in the forum?
Update!
Put a timing light on it and when on the bottom sparkplug wire I can see both 1 and 2 timing marks sporadically.
When on the top sparkplug I consistently see only one timing mark.
Would this explain my problem of misfiring? What is the cause?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,819
Switch the coils and test run again.----Keep timing light pick-up away from other wire.
 
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