Home › Forum › Ask A Member › Mid 50’s Johnson 25HP runs like crap. Advice needed › Re: Mid 50’s Johnson 25HP runs like crap. Advice needed
When you pull the plug on the good cylinder it runs poorly, as you mentioned. That indicates it is sparking, but it does not mean the ignition is "good". I have had several motors run well on one cylinder and poorly on the other. It would be well enough to keep it running at full throttle or near that, but if you put neon spark testers inline with the plugs and run it with them, you should see your bad cylinder showing weak and/ or intermittent spark. That is assuming it is ignition and not induction. It’s easy enough to check the reeds and rule them out. This issue has always been ignition for me, but reeds are certainly a possibility.
-Ben
OldJohnnyRude on YouTube