fouling plugs on golf cart

[Chevy1500z71]

my rotax 503 was fouling plugs in 1 cylender after only a couple rides on a 290 main jet, so i switched to a 280 and the plugs last longer but still eventualy foul. the moter was jeted for cold wethether and higher elevations im asuming since its out of a snowmobile. but what im wondering is if the moter is jeted richer for cold wether, i dont want to go to leen...

[TRX450R_Racer]

It should be jetted richer for colder weather.

[Chevy1500z71]

It should be jetted richer for colder weather.

thanks, thats what i was thinking, i was afraid that i was going to end up going to leen whene something else may be my problem. going to try a 270 or a 275 and see what hapens. it seems the leener i go the longer the plugs last... i hjust dont wana go to leen

[TRX450R_Racer]

Try dropping the needle down one notch.

[Chuck_Norris]

Try dropping the needle down one notch.

Good call, check and see what pilot jet is there also. does it foul it out at idle, part throttle at W.O.T
 pilot Jet and mixxer screw play the role at idle..Needle is your mid range and YOUR Main jet is  for W.O.T
 

[Chevy1500z71]

Try dropping the needle down one notch.

its down all the way

Try dropping the needle down one notch.

Good call, check and see what pilot jet is there also. does it foul it out at idle, part throttle at W.O.T
 pilot Jet and mixxer screw play the role at idle..Needle is your mid range and YOUR Main jet is  for W.O.T
 

i have no idea where its fouling plugs wether its idle or full, but it runs about 6500 90% of the time, wich is prety far from wide open