Reply To: Johnson FD-12 Won’t Run

[Don]

billw wrote:

To me, if I looked at those two plugs, I would be thinking I had poor spark on the one that is NOT fouled, as it doesn’t even look like it fired much at all. If you don’t have true, open-air spark testers, you can just rip the ground electrodes off regular plugs, creating a bigger gap. A good OMC ignition will jump that gap in open air.

I agree, this is often true.  Many times it is the clean plug that isn’t firing.