69 40hp Pinned at WOT, but wont go fast

Tim Frank

Vice Admiral
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Jul 29, 2008
Messages
5,346
According to my chart, the OEM plug should be UL81C gapped at 30 thou.
Never heard of that plug, but it may be easier to get than I'm thinking.
 

Chrisravosa36

Chief Petty Officer
Joined
Aug 16, 2015
Messages
622
Il order a pair. So I didn't have anything to pull the plugs with, so I tested running each cylinder at a time. I started with the old plugs, one cylinder would just barley start, it would die on and off with the starter, but wouldn't stay running without the help of it. The other one would only run at a pretty high rpm. Tested with the new plugs, both ran perfect, no problems. Could it be that I had just worn out plugs? Also, the air/fuel mix I was playing with it, and the cover was so brittle it snapped. The rich lean knob is still there, just don't know which way I should adjust it. Is this the low speed or the high speed knob? And do I adjust lightly seated or what?


My manual STILL hasn't come yet.....
 

Chinewalker

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Joined
Aug 19, 2001
Messages
8,902
Actually, the recommended plugs are Champion J4C. If you do extended idling (trolling) then you can use J6C plugs. No idea where the UL81C plug rec came from... It's an extended length plug, 1/2-inch reach, and likely to hit the piston.
 
Last edited:

lindy46

Captain
Joined
Nov 27, 2008
Messages
3,886
Also, the air/fuel mix I was playing with it, and the cover was so brittle it snapped. The rich lean knob is still there, just don't know which way I should adjust it. Is this the low speed or the high speed knob? And do I adjust lightly seated or what?


My manual STILL hasn't come yet.....

That motor should just have an adjustable low speed needle. Lightly seat it, then turn counter-clockwise 1.5 turns to start. Yes, switch to the Champion J4C or J6C plugs.
 

Tim Frank

Vice Admiral
Joined
Jul 29, 2008
Messages
5,346
Actually, the recommended plugs are Champion J4C. If you do extended idling (trolling) then you can use J6C plugs. No idea where the UL81C plug rec came from... It's an extended length plug, 1/2-inch reach, and likely to hit the piston.


Some idiot (that would be me :)) looked at the wrong year.:facepalm:
Apologies to the OP, and a reminder that not everything that you read on the internet is correct.
 
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