Carb
also check the carb needle hasnt jumped. There are 2 positions. The wrong 1 will only let throttle rev engine a bit before engine cuts out. Could be dirt in carb as well? Mine had dirt, exhaust was smoky, carb dirt cleared and so did smoke.
Elec start switch is a crap design, had mine apart, cleaned it, then it started working - only to prove i had a battery which spun the starter a tiny bit b4 giving up!
steve
October 2011