A couple weeks ago I bought my wife a 04 blaster the people we got it from said that just rebuilt it but I started to have problems right away so i brought to a shop thay rejected the carb and put a new stator in it it was good for a week then the throttle started to stick then it back fired and sezed up so I pulled the moter apart the jug and piston don't look to bad but the crank is locked up what should I do