I have a 2000 500 Quadmaster that wants to spit, sputter and backfire at about half throttle. Idles fine and comes up to about half throttle then it falls flat on its face and backfires and spits and sputters. I am doing this all in neutral so I don't know if there is some sort of override or not. Initially I pulled the carb off and cleaned it out because it wasn't idling properly, that is now fixed. I checked the diodes in the voltage regulator per the service manual and it did fail a couple tests so I put a new one on, but it is still doing the same thing. Any suggestions?

 

Automatic?

 

Yes it is automatic, hi, lo, reverse, park and neutral. No shifter

 

The question of whether it was an auto made me think there might be some sort of neutral rev limiter. I put the quad somewhat back together and took it out. It ran 100%. I am thinking it had to be in gear to get its full potential. Just in case anyone has the same problem... try putting it in gear.