Surface Gap Spark plugs

[THEFERMANATOR]

Originally Posted by Destroyer

I completely agree that given the choice go with the gapped ones. but look up your engine specs though. Some engine manufacturers specified surface gap plugs instead of gapped plugs. I always go with what the engine maker calls for.

I do as well, but sometimes they reccomended both styles, one was for general use, and the other for sustaned high rpm runs. Omc used to do this with the ql77jc4 gapped plug for general use, or the ql7iyc which had an extended electrode for sustained high rpm use. They worked great if you were running 5K+, but idlefor 5 minutes trolling and they were all fouled. Put ql77jc4's in and no more fouling.

Or how the early 80's cross flow omc outboards origanally used surface gap plugs, but omc changed there reccomendation in the 90's due to fuel changes, and now they call for a gapped ql77jc4 unless it's on a performance boat in which case you can still run the surface gap plugs to minimize detonation.