Correct Spark Plug for '82, 25 hp Merc???

[b22smith]

I have bought a used 1982, 25 hp Mercury outboard and I want to make sure I'm using the right plugs. What brand of Champion or NGK plug is specified and the gap?

 

[dilligafda]

Re: Correct Spark Plug for '82, 25 hp Merc???

NGK B9HS-10 is the plug I would recommend and the gap is .040.

 

[Redonthehead]

Re: Correct Spark Plug for '82, 25 hp Merc???

maybe they changed, but my '85 model uses a surface (fixed) gap plug.

 

[dilligafda]

Re: Correct Spark Plug for '82, 25 hp Merc???

Yup, the Merc recommendation changed. It was a Champion L77J4 and changed up to the NGK number.