Spark plugs

[mmckelvey]

I have a 1957 18hp Johnson and was wondering which spark plugs I should use. I have used the Champion J6C(long ones)and the CJ6(Short ones). and the engine seems to only start with the CJ6 plugs could anyone tell me which plugs are the right ones to use because I was told the J6C plugs were the proper ones to use.<br /><br /><br />

She said fishing or me....... I'm gonna miss her

 

[Paul Moir]

Re: Spark plugs

J4C or J6C gapped at .030"<br />J6C is hotter and will give you better trolling, but for normal or high speed use use the J4C.<br />Perhaps your J6C's were bad out of the box, they should have started it. Any sparkplug that physically fits should start the engine afterall.<br /><br />By the way, the original spec plugs were J4J and J6J, but they've been discontinued in favor of the nearly identical C plugs.