Which is the right spark plug?

[dfrants]

picked up a 1977 Johnson 6hp 6R77M. I believe this was the first year with CDI. I know OMC used Champion plugs so I went to their on-line catalog and looked up the plug. It recommended QL88C. I have an old Champion catalog from 2003, it shows L86C. I then went to Crowley Marine, they list QL77JC4. Which plug is the best to use? or does it even matter?

 

[F_R]

I don't trust Champion's catalog lists any more. But a list that I do believe says QL77JC4 or QL86C. I suppose whichever one works best for you.

 

[Vic.S]

I agree with F_R

QL77JC4 or QL86C, Gapped at 0,030"

L77JC4 and L86C are non-suppressed versions and would also be suitable.

What matters is that you dont use a resistor suppressed plug such a NGK BR7HS or BR7HS-10 which you'll often find listed a equivalents ... They are not

( The NGK equivalent is BZ7HS-10 )

 

[Spartans]

QL77JC4 is best