Love what you do on Youtube! This may be a bit out of the ordinary... In the last two years, I have had two sets of sparkplugs fail mid-season in my 2001 Mercury outboard with ~700 hours (115hp 4-stroke EFI). It's my commuter vehicle at my homestead. Anyway, zero prior failures. I have always done the maintenance on this OB. I winterize it once/year and ALWAYS wipe the plug threads and pack a bit of anti-seize into the threads before reinserting (after oiling the cylinders and cranking the engine to distribute). The Q: If I ever over did the anti-seize, could the compound eventually short out the spark? I tried to measure resistance of the failed plugs but my meter didn't show me anything obvious. Any ideas?. THANKS!
When you have steel and aluminium coming together, they can interact with a galvanic action and actually seize to each other. And so, I always smudge a tiny bit of anti-seize onto spark plugs. The problem, however, is that with anti-seize applied, you will over-tighten the spark plug by about 20% with a spec set torque wrench - less friction between aluminium and steel. So be careful. Cut the torque spec setting by 20%
F.S.
No, it's electrically non-conductive. But don't just plaster it all around, just put it where it needs to be (on the threads), not on the electrode. Our mechanic uses a trimmed-down acid brush to apply anti-seize, makes it very easy to control exactly where it gets applied and how much is used.
@oldrangernut
Anything is conductive with enough voltage. Even air ... In fact that's exactly how spark plugs work. Anti seize is loaded with metal.
NGK recommends not to use antiseize on their spark plugs:
https://ngksparkplugs.com/en/resources/5-things-you-should-know-about-spark-plugs
"NGK spark plugs feature trivalent plating. This silver or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without lubrication or anti-seize."
