Ran well most of this season but now surges. Replaced fuel filters, cleaned the carb, seems to have too much air. With my thumb covering 1/2 of the air intake to the carb it runs smooth. It does run smooth at highest speed but cuts out at 1'2 throttle. Dealer will ultrasonically clean the carb for me but I had it off and thought I cleaned it pretty well already. Any suggestions?
Also where is the serial number?
Also where is the serial number?