2000 -65hp Comm Johnson / spark plug fouling

Sinkbox

Recruit
Joined
Oct 18, 2009
Messages
2
I am continiously fouling the recommended QL16V or L16V Surface Gap Spark plugs. Can I sub these plugs with another Gap type. I am using hi-grade oil with 50:1 ratio mixture. Note: Lake water temp is 50F or lower.
 

jeff_smith_0423

Chief Petty Officer
Joined
Dec 5, 2007
Messages
492
Re: 2000 -65hp Comm Johnson / spark plug fouling

The commercials specified the surface gap plug more often than not. I think this is supposed to be from a maintenance standpoint and not an interference issue. The non-commercial versions of that motor use the QL77JC4 gapped to .030. Hopefully someone who has seen your exact motor can tell you if it is safe. The heat range should be fine - just need to make sure you have piston clearance.
 

Sinkbox

Recruit
Joined
Oct 18, 2009
Messages
2
Re: 2000 -65hp Comm Johnson / spark plug fouling

Tks Jeff,

Just picked up 6 - QL77JC4 & there is enough clearance. Anything got to be better than than the QL16V or L16V Surface Gap.

Regards,
Sinkbox
 

jeff_smith_0423

Chief Petty Officer
Joined
Dec 5, 2007
Messages
492
Re: 2000 -65hp Comm Johnson / spark plug fouling

Tks Jeff,

Just picked up 6 - QL77JC4 & there is enough clearance. Anything got to be better than than the QL16V or L16V Surface Gap.

Regards,
Sinkbox

Heh. Should resolve it if you've got a fouling issue but keep an eye on them. I posted a very opposite thread, as my old Merc's ran wonderfully on them and they're specified as an alternate plug for my 25hp Johnson - but the answers came fast and furious. "Don't even bother" was the general tone.
 

gmorris

Cadet
Joined
Sep 14, 2007
Messages
7
Re: 2000 -65hp Comm Johnson / spark plug fouling

I have the same engine and had the same problem as you. I switched to the ql77jc4 plugs 2 years ago and have had no problems since.
 

jeff_smith_0423

Chief Petty Officer
Joined
Dec 5, 2007
Messages
492
Re: 2000 -65hp Comm Johnson / spark plug fouling

Thanks for letting us know! I'm always hesitant to say "this *should* work" when I don't have any evidence or something to verify against.
 
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