you most likely have an air leak. first check to make sure the clamps on the carb are tight and the bolts that hold the rubber boot that the carb goes into. also look at the boot for cracks. A 2 stroke engine needs to be airtight to run right...sucking in air causes a lean condition and could blow your motor up. I would suggest to buy a leak tester and test it before you run it again...also make sure the carb is getting enough gas that could cause the high revs