Originally Posted by JaySpencer

If I recall correctly, the butterfly valve should be attached to a rod that activates it. Sounds like the spring or actuater is shot or missing. If that is the case, you may have a few solutions, like trying to replace it with a new spring, or rebuilt carb al together.

I have seen people who have gone so far as to rig a manual choke with something as "cheap" and "simple" as parts gotten from a bike shop.