Spark plugs

[Rhigley]

What is the difference between marine spark plug and a auto spark plug?

[bondo]

Ayuh,..... Depends,.....

With AC Delco, for the Chevy motors, the auto plug is R43T, a steel bodied plug,....

The Marine version is MR43T, an alloy bodied plug, much less prone to Rust,....

[chawk_man]

And less prone to meld with a cast aluminum head. However, it's still a good practice to pull the plugs and inspect every season. Then when you re-install put a light coat of high-temp grease on the threads.

[makomark]

The plating on the metal shell....in the better quality plugs.....