1988 Johnson 150 GT Plug Gap

dgoock

Cadet
Joined
Nov 15, 2010
Messages
12
The manual calls for gapping the Champion QL77JC4 plugs to .040", but I have seen recent specs calling for .030". What is correct?
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1988 Johnson 150 GT Plug Gap

The factory calls for .030 gap on that plug.
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,690
Re: 1988 Johnson 150 GT Plug Gap

Yep originally 0.040" but the specs were changed some time ago to 0.030"
AFAIK right across the board.

I believe the change is supposed to improve plug life.
 
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