Johnson 1974 15 HP Sparking Issue

BROUSSARD2

Cadet
Joined
Mar 20, 2018
Messages
25
I have a Johnson 15 HP 1974 that is sparking well on the top cylinder but the bottom cylinder has a weak spark. It has a PSI of 120 on both cylinders. Any ideas on what to check to verify what is causing the weak spark on cylinder 2? The motor will backfire every now and them but will not attempt to start at all. Ive taken the flywheel off, the points look good and I lightly sanded them to make sure there was no corrosion. Any ideas or troubleshooting tips appreciated.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
First off.-----" sparking well " is not a technical term that can be understood.-----What gap will the spark jump on the 2 leads.----1/16"----1/8" ----1/4" or 3/8" ------That means something in trouble shooting.
 

BROUSSARD2

Cadet
Joined
Mar 20, 2018
Messages
25
Sorry I should have been more specific with how I tested this. I just used a spark light tester. The light is very strong on the top cylinder but very dim an not clearly visible on the second cylinder. I need to buy a gap tester and give you the results.
 
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