15 hp Johnson spark plugs

Jack Shellac

Lieutenant Commander
Joined
Aug 7, 2002
Messages
1,661
Re: 15 hp Johnson spark plugs

This is correct. Source: manual for same motor. Gap: .030". You can also use a QL77J4 if desired.
 
Joined
Aug 12, 2002
Messages
7
Re: 15 hp Johnson spark plugs

Thank you for the info. The plugs are very worn and need replaced. What are the differances between the plugs if any?
 
Joined
Aug 12, 2002
Messages
7
Re: 15 hp Johnson spark plugs

All I can find online is a L77JC4 and QL77JC4. Are these the same plugs just updated numbers?
 

Jack Shellac

Lieutenant Commander
Joined
Aug 7, 2002
Messages
1,661
Re: 15 hp Johnson spark plugs

Glad you asked question. Correct gap is .040" [ I was thinking of another motor]. OMC recommends either plug. Your numbers are the new Champion number for these plugs.
 
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