The sometimes get loose and because of excessive clearance will bind causing your problem. Fast idle should be set at 2000 rpm.

Tech Install An Electric Choke On Your Manual Carb
Holley fast idle cam sticking. Slightly crack the throttle open unload the fast idle cam and turn the choke cap clockwise until you see the choke plate open. Maybe a spacer or washer missing somewhere. At that point is the choke plate wide open or not. Polish the connecting parts and use thin washers to take up any extra slack but the cam must still move freely without binding. I tightened it after the high idle issue. Holley fast idle hanging up so what your saying is the fast idle arm is still making contact with the fast idle screw when warmed up.
The fast idle cam should move freely with the engine warm or the linkage un hooked. Loosen them up just enough to allow you to rotate the choke cap but not enough to allow it to freewheel. Try giving the carburetor a little gas at the throttle arm and make sure the choke plate is wide open. Theres probably a rod that connects the choke valve to the fast idle cam. I actually just tightened the return spring because it was pretty loose. It might fit together ok but stll not allow for full free travel of the lever cam or linkage rod.
One of the ways to get a good starting point is simply to loosen up the choke housing screws on the retainer. Adjust fast idle screw as needed. Some carbs might allow you to install this rod backwards or upside down.