it sounds like the idle is too low or the carb is closed and its not starting. pull the air filter off and see if there is a open gap. the carb should always be open a little. if its open and still not starting then there might be something else wrong.check your clutch bell see if it spins freely if it dosent then you may have broken some shoes and need replacing.there arent that many things that will stop this engine or other 2 strokes from running. 1 air filter may need to be cleaned and re oiled, 2 check your clutch shoes, 3 check your idle gap it should be between 1 and 2 mm, 3 the o ring on the tank, 4 your low speed needle. thats pretty much it. if you want spray some wd40 in the carb opening that should get rid of some crud in the engine them rinse it with after run oil to get the wd40 out . hope this helps