Spark plug replacement options

[opposedtwin]

Believe it or not, I have never bought a spark plug from a store or dealer for an outboard motor. Some years ago I bought a whole bunch of very slightly used J6Js from a fellow member at a chapter meet. He was a very credible source who told me these were plugs they used at the factory to start and adjust the new motors. The plugs were then removed and replaced with brand spankin’ new J6J plugs. Anyway, I have been using them for years without issues but I have finally run out.
I see from Peter Hunn’s book that the J6J was replaced by the J6C. Is the J6C still available at stores or has it been superseded?

Pretty sure I saw a thread about plugs awhile back but I have found that our search tool has always been awful.
Thanks for any help.
Scott

[dan-in-tn]

J6C Champions are readily available.

Dan in TN

[dave-bernard]

the difference in j6c’s is the side electrode is longer. to make j6j just file the electrode shorter to cover 1/2 the center electrode.

[frankr]

The shorter side electrode was intended to prevent wet fouling. A second benefit is it presented a sharp edge for the spark to jump to. A spark will arc to a sharp edge or point easier than to a flat side. That’s why lightning rods are pointed.

With today’s oils, the wet fouling doesn’t seem to be much of a problem any more.

[outbdnut2]

I’ve replaced J6Js with J6C’s in lots of motors with no problems.
Dave

[Chris]

Wow, learn something new everyday. I always wondered what the difference was. Thanks Dave Bernard and FrankR.

[Author]

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