Oh, that's the bolt you're referring to. That is supposed to be there. It limits how far the arm can travel on the 4600 V2 and V3. When the lever is lifted all the way up and that screw is hitting the little post on the carb casting, that is the idle position. Your throttle handle grip should be rolled all the way forward at this point and then lock the cable to the pulley. Looking down the throat of the carb, the barrel should be half closed. When you roll the throttle hand grip back, the lever on the carb should move down and the barrel should open. If, by the time you roll the hand grip all the way back, the barrel doesn't open completely, you have to try locking the cable on the pulley at a different position, so that when you roll it all the way forward, the barrel closes halfway and when you roll it all the way back, the barrel opens completely.
When you're having this high idle problem, is the motor still on the tire? Or is it when you have the motor lifted off the tire?