Plug type

[ArneA]

1964 Evinrude 18hp..Charts call for two plugs,,a B6S and a B8S NGK....Can someone tell me the difference and which plug is recommended for the Fastwin 18HP ?

 

[boobie]

Use a Champion J4C. OEM recommended.

 

[JimS123]

No Evinrude chart ever specified an NGK spark plug.....LOL.

Back in the day that motor called for a Champion J4J. The general recommendation later evolved into a hotter plug (J6J) for better performance. The current offering is a J6C, gapped at 0.030".

I have two '60's Fastwins (that's what you have) and I guarantee that plug will make your motor happy!

 

[boobie]

Plug heat range depends on how you're using it.

 

[ArneA]

Thank you for all your help....

 

[Vic.S]

1964 Evinrude 18hp..Charts call for two plugs,,a B6S and a B8S NGK....Can someone tell me the difference and which plug is recommended for the Fastwin 18HP ?

The difference is 2 heat grades. The numbers for NGK run the opposite way to Champions so B6S is hotter than B8S

B6S is the nearest equivalent to J6C

B7S is the nearest equivalent to J4C

I suspect B8S will be too cool

 

[JimS123]

Plug heat range depends on how you're using it.

The "cold" plug will work well if you do a lot of high speed running, but it won't like idling for long periods and will eventually foul.

The hotter plug will work better if you do a lot of trolling or other slow running, but it will work equally well for a lot of high speed running.

Thus, its a no-brainer.