Marine spark plugs

hondarider188

Petty Officer 2nd Class
Joined
Jun 15, 2011
Messages
160
I have a 1984 Evinrude 140hp and it has a hard time idleing but it runs great when the rpms are up. So it seams that the plugs are loading up until it runs higher and cleans out. I heard that the surface gap doesn't idle very well and load up easy while the regular plugs do much better.What I was wondering though is if I can use regular plugs instead of the surface marine plugs that are currently in it to help the idleing and what is the difference to begin with?
 

hidef

Lieutenant
Joined
Aug 22, 2009
Messages
1,465
Re: Marine spark plugs

Yes switch over to the QL-77 spark plugs. Your engine will actually idle better and you will not see any loss of performance. The surface gap UL-77 plugs are great for two speeds WOT and off. The surface gaps are very prone to fouling as you have found out if you do any type of idling.
 

hondarider188

Petty Officer 2nd Class
Joined
Jun 15, 2011
Messages
160
Re: Marine spark plugs

Thanks but 1984 is the only year that the plugs are not mentioned on whether you can use the regular or surface gap while for 1983 1985 are. So what I was worried about is if their is not enough clearance for the piston to use the regular plug.
 

Lyle29464

Lieutenant
Joined
Mar 10, 2009
Messages
1,261
Re: Marine spark plugs

put a dab of grease on the plug and roll engine over. ( just like checking the bug in a dist.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: Marine spark plugs

The parts link I posted is for a 1984.
The item #34 is the plug, there are 4 listings, the forth listing shows a QL77J4 to fit the 140hp.
 
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