problem started with the engine cutting out at higher rpms under load. it got worse to the point where now the only way i can even get it started is to rapidly hit the starter button repeatedly or hit it as pulling the cord. if i hold the starter button down it has no spark. when it dies after reaching just above high idle it is as though a certain rpm triggers the ing. to shut down. same rpm every time. idles fine but as soon as i hit the trottle dead at the same rpm.. i'm frustrated and would appreciate some advice and or info to help w/prob.. thanks in advance-- AV