Calflyer its not you its your motor, the ST90 are unreliable (at least mine were). I had 2 early this season and they would fly for only 2 minutes then I would have a dead stick. Me and a couble guys tried every thing from low end needle, high end needle, plugs, fuel from 0% to 15% with absolutly no luck. GOt me a ST75 and and have about 30 10 minute flights with no problem...