Hello. I bought a used hart cart utv. please don't laugh im in pain. It has a 300cc Yamaha engine and is not working very good. It starts and runs fine It idles fine, even at 100% lean (mixture needle totally closed) and will rev up without hesitation in neutral. But put in gear, and start to move, within 100 feet it chokes and comes close to stalling. I've tried to enriched the mixture, no change. If I stop and let it idle I can take off again but starts having these symptoms again. It never dies completely. Some times it runs fine. Any ideas what the problems are. Fuel?? ignition?? this is driving me nuts. PLEASE any input would help ease my pain.

 

Check fuel supply, sounds like carb' isn't getting enough. Filter? or even breather hole in filler cap?. Also check for crap on the slide, (change to foam twin-air filter).