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95 Merc 350 Magnum Tournament Ski Spark Plug Thread Repair

pwskicat

Regular Contributor
Replacing spark plugs today and one turned easy-hard-easy on the way out. Compared to the other plugs with clean seats at the top of the threads, this one looked like it had blow-by on it. Put in a new plug and it turned in easy all the way, but wouldn’t tighten on the last turn. It just gets a little tight, then goes loose.


Repair options: Heli Coli Kit ($35), Fix-A-Thred ($30), 14 x 1.25 tap ($10). Recommendations welcome.


Also need a recommendation for the right plug socket. I have a Duralast 5/8 deep well that works, but it ain’t easy on most of the plugs and won’t work at all on two cylinders where the exhaust manifold gets in the way.


Watched a few youtube vids this one was informative, and the guy’s pretty funny too. https://www.youtube.com/watch?v=B3irFj2XeCM


Planning on naming my boat: “If Anything Can Go Wrong…”

 
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