RE: Need advise badly
Tom:
Almost without question you have an air leak. Smear "BlueGlue" over all joints, around the base of the carb, and on the carb retaining screws. It will lookugly, but you aren't going to leave it.
Set the idle, then while the engine is running carefully pull the BlueGlue off a bit at a time. When the engine acts up again you've found the leak.
Bill.