1966 Evin. 18hp spark plug discrepancy?

I just bought this engine and it's got Champion J4C 's in it. I went to get replacements this AM and the guy said it actually takes J8C 's. I think one is hotter than the other but I don't know....I've already ordered an orig. manual but in the meantime I'd like to get the right ones in there. BTW - it is running fine w/ the J4c's in there. Any insight would be appreciated...thanks! This site looks awesome ... just found it today.

Re: 1966 Evin. 18hp spark plug discrepancy?

Hi, Adam.<br /><br />Just to confirm, your model number should be FD-20.<br /><br />OMC specified the Champion J4J (the modern equivalent is the J4C), gapped at .030.<br /><br />The J6C, which many later OMC engines use, is a bit hotter and might be used for long periods of low speed operation or trolling, to reduce the chance of fouling. It should not be used for long periods of high speed operation.<br /><br />I would not use a J8C in any water cooled 2 stroke. It is hotter than the J6C and is intended for air cooled 2 strokes like lawn mowers and chain saws that use much more oil-rich fuel.<br /><br />Stick with the J4C.<br /><br />Good luck.

Re: 1966 Evin. 18hp spark plug discrepancy?

thanks very much - great info