I have a yamaha blaster and when i start it up and it revs out on its own so high does ayone know wats wrong?

Did you R&R carb?? It could be the throttle valve stuck. It is not on the groove The carb body have tab. The throttle valve have groove on one side and not matching. It is stuck open. You need to turn the slide valve till it go down. The throttle valve have cutway. That go to " airfilter direction"