I have a Craftsman with a Briggs 12.5 IC Gold. The RPM's are out of control on this thing. I can adjust it to rev down a bit with the throttle all the way down. Once you add the slightest throttle it revs out of control. I'm waiting to catch shavings in my face. The carb is fine. It is clean and new fuel/air components are in. The mixture screws are adjusted appropriately too. The problem existed before the carb work but for how long I don't know. I think it is something engine related.....valves? Also where do you access the valve clearance adjustment. The manual leaves little to be desired. HELP MEEEE!