And on older carbs, sometimes just jiggling the linkage is not enough if it's gummed up.
Easiest way to clear that up is a quick dousing with Chemtool and then a few shots of WD-40 to lube it up.
Or a reasonable facsimile thereof...
Like Viper said though, if it's not simply gummed up, your adjustment is off too. It should not start out at 800. That's near a normal hot-idle once the choke is open. When cold and the choke is on, the idle should be in the 1400 rpm range.
Next time the engine has cooled off, pop the air filter off and manipulate the throttle linkage and watch the choke plate and mechanism. As soon as you pull the throttle back, it should spring closed and the stepped fast-idle cam should rotate up/down so that the fast-idle screw (cleverly hidden down under there) contacts one of it's higher "steps" and holds the throttle open slightly.
This is all sometimes hard to see down there beside the choke housing, but you can go back and forth until you see just what's moving and when.
As you manually rotate the choke plate open with one hand, and open the throttle slightly with your other, the fast-idle cam should rotate with it and eventually break contact with the fast-idle screw. When that happens, your throttle lever should only be in contact with your normal, or "curb" idle screw.
Clean and lube all the little pivoty-thingies down there and see what happens.
Good luck.
Paul