Fast idle issuse

May i make a suggestion. If you haven't done it already, and there truly is movement between the carb body and baseplate, please pull it, turn it over (be prepared for the fuel to drain out) and make sure there are no loose baseplate screws in a position to fall down the intake and make mincemeat out of a valve and or a piston top.

It's actually movement on the throttle shaft but its not much movement enough for me to question it