1987 Mercruiser 3.0l spark plaugs

[lojack]

My engine currently has ACR42T and the marina recommended Champion RV15YC4. However, I was told by an online parts store that the RV15YC4 was too hot and I should use the RV9YC. I bought the RV15YC4, but will they be ok in my 1987 engine?

thanks!

 

[Don S]

Re: 1987 Mercruiser 3.0l spark plaugs

You should be running an AC MR43T. Forget Champion plugs.
Head up to the Adults only sticky and download the manual. All the plug info is in it.
You want manual #10.

 

[cr2k]

Re: 1987 Mercruiser 3.0l spark plaugs

Ngk yr5