Re: why wont my thundertiger gp42 rev at full throttle for long before cutting out

Sounds like it could be the same problem as the GMS 47. Try backing out the idle screw (make it richer). Set up the high end before the idle. Then after each idle adjustment, reset the high end again.

The Thunder Tiger GP series engines use air bleed carbs so the reverse is true. Basically, you set the high speed for proper running then adjust the airbleed in for richer and out for leaner. If the engine will not run at more than half throttle, there is something restricting fuel flow since the main needle does all of the fuel meterings and the air bleed only compensates for the richer mixture at low throttle openings.