Choke doesn't seem to work as it should

Carb has two idle circuits. When cold, choke partially open, the linkage swings up into place a 'fast idle cam" with its own adjuster screw. Adjust cold idle here, maybe 900-1000 on the last step. When warm this cam swings out of the way and you can adjust the "curb" idle. If you have a stumble when it is warm, that is another issue.