I have a 99 Polaris Sportsman 500 with a 40 millimeter carburetor on it and is running rich. as soon as I put it in park and give it gas it spits and sputters and bogs down . there is no backfiring whatsoever out of the exhaust or out the carburetor. But as I take off the air filter and air box it somewhat straightens out. I rebuilt the carburetor last year. I took the spark plug off and it is black as the ace of spades, leading me to believe that is running rich. I took apart the carburetor last night and everything still seems to be pretty clean. This one has got me stumped
Any advice would be helpful
thanks