is fuel coming out of the bowl overflow? the little tube on the lower rear of the carb. the float level may be out of adjustment. when the fuel raises the float it cuts the fuel supply off, if this is out of adjustment too much fuel enters the bowl, what can't get out the overflow goes into the motor causing a rich/flooding condition. remove the carb, get a piece of vacum line or hose that will fit on the carb supply,(where the fuel line from the tank plugs on), hose needs to be 12" or so. take the bowl off,hold carb upright(like it sits when installed, at eye level, needs to be level, gently!! blow through the hose while pushing up on the float. if it goes past parellel of the bottom of the carb that may be your problem. you'l have to bend the metal arm conecting the float to the needle valve. check your manual for the exact setting. the service manual explains this pretty well. if you don't have one i recamend getting one! good luck.