How can you repair a spark plug hole that isn't working?

How do you rethread a spark plug?

Rethreading a Spark Plug Hole

1. Run a commercially-available spark plug "thread chaser" tap of the correct size into the existing damaged spark plug threads and try to clean them up.
2. If the threads are too damaged to repair with a thread chaser, purchase a threaded Insert Kit and insert the insert into your spark plug hole.

What about spark plugs? The bottom line: JB welding cannot withstand the compression pressures from an outboard motor.

What is the cost of repairing a damaged spark plug?

You can find a qualified mechanic to insert over-the-fender threads for as low as $500. If you need additional plug hole inserts, it will cost you even less.

Are helicoils permanent or temporary?

Helicoils can be used as permanent repairs. They are a permanent repair if they are installed correctly. You can damage the Helicoil if you use a cross-threaded bolt to thread it in.