15 hsp johnson

[rrapp]

The model number is 15R74S. I am trying to determine the proper spark plug gap. I bought the<br />motor from a dealer last year. The old plugs were Chapion L77JC4's. Sorry I am not sure of the year.

 

[Peter O]

Re: 15 hsp johnson

The motor is a 1974. Hope this helps with your question.

 

[Allan19603hp]

Re: 15 hsp johnson

For a 1974 Johnson or evinrude there should not be l77jc4 plugs.. these motors from 74-76 had a breaker point ignition system. Is the motor experiencing problems with idle and power. Unless the igniton system was converted and runs off a power pack then I would check into the plugs.<br /><br />Allan

 

[jegervais]

Re: 15 hsp johnson

The manufacturers recommended spark plug is a Champion UL81C gapped to .030".<br /><br />-John