1984 Johnson 15hp Issues

AATA

Cadet
Joined
May 18, 2009
Messages
28
I bought a 1984 Johnson 15 hp for really cheap but it wasn't running. Owner had a diagnostic from a shop for CDI so I figured that's what it was and it didn't have spark. So I installed a CDI and it has great spark now on both plugs. I felt confident that it would solve the problem, but when I try to start it (it's electric start) it won't start and backfires every so often. I thought it might be a fuel issue because the plugs were dry, so I pulled the carb and it's perfect. I then tried putting a little fuel directly in the cylinders and it still just backfires. Compression is at 87 on both cylinders, which I believe is inline with what it should be. Can timing be off on these motors? That's what it sounds like, but I'm not familiar with how to set timing. MOst of my experience is with motorcycle engines, so this engine is a little new to me.

Where should I start with figuring our why it's backfiring.

Thank you!
 

AATA

Cadet
Joined
May 18, 2009
Messages
28
Re: 1984 Johnson 15hp Issues

Nevermind. I read in another thread about mixing up the wires. I thought there no way i did that, but checked and yep, mixed up the plug wires. I feel dumb, but easy fix! Runs great!
 
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