spark plug hole size

[jonespj]

I'm getting a leak down tester and need to find out the size m. meter plug hole is in a 1985 mercruiser 3.7, 4 cyl. Would appreciate that info. Thanks, Paul

 

[jonespj]

Re: spark plug hole size

The leak down tester I'm looking at on line comes with a 14mm & a 18mm fitting . Will that work on a 1985 mercruiser 470? It's a ProForm brand. Thanks in advance for any help. Paul

 

[Don S]

Re: spark plug hole size

14 mm is what you want.

 

[stonyloam]

Re: spark plug hole size

14 mm. Don was a little quicker, at least we agree LOL.

 

[jonespj]

Re: spark plug hole size

Great! Thanks