1965 Johnson 6hp spark plugs

[Evinrudej]

Can you run J8c’s on a 1965 Johnson 6hp is it too hot of a plug?

 

[racerone]

These used a J4J ( J4C ) when a thermostat is installed.-----Will idle smooth all day.-----Yes , they can run with a J8C as well.

 

[Chris1956]

Can you not get J4C? They used to be readily available. Advanced auto parts stocks them, but I would think amazon does as well.

 

[Vic.S]

The recommended plugs are J6C.
.

 

[racerone]

Parts book shows J4C---And it should run / troll all day long with those.

 

[Evinrudej]

Can you not get J4C? They used to be readily available. Advanced auto parts stocks them, but I would think amazon does as well.

I can get j4c and j6c but I just purchased the motor and the previous owner put new champion j8c’s so I don’t see any reason to change them if I don’t have too. Checked the gapped and they were at .030

 

[Chris1956]

They are a bit too hot for that motor. Since the motor is water cooled, it will probably (probably) be fine, but you should inspect the spark plugs for a greenish tint. If you see it, the motor is likely overheating, at least in the combustion chamber.

For $5 you can put the factory specified plugs in it, and not worry about it.