90 Yamaha plug fouling

rwunstel

Cadet
Joined
Mar 15, 2008
Messages
22
Bottom plug on 90 Yamaha will foul only if it is run wot. I can run for ever at 1/2 or 3/4 throttle and never foul a plug. It takes about 10 miles before the plug fouls if I run it wide open. Idles great and runs good. Any suggestions. I know very little about Yamaha motors. Oh its a 3 cyl 2 stroke.
Thanks
 
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