Engine goes right to full throttle/advance

Well, an engine won't rev up from fuel alone. It must be getting air and fuel from somewhere.

There is a fast idle adjustment on these carbs. When the choke closes it rotates a cam that interferes with the fast idle adjustment screw. Just pulling the choke open won't drop the fast idle, you have to whack the throttle once it gets warm and the choke starts to come off. You can, of course, back the fast idle screw all the way off.