Incredibly Fast Rev After Routine Maintenance

The fast idle cam only swings around to function with the closing of the choke. When the engine initially starts cold, it is opened slightly by a vacuum diaphragm which sets the fast idle cam to about mid-ramp. Then as the choke opens it swings out of the way to curb idle. Sounds like diaphragm is not working (not allowing the cam to reset) or you bumped the linkage and jammed it temporally. You need to replace that screw and spring to restore fast idle function, not doing so opens the possibility of this happening again.