When you manually close the choke, how much pressure do you have to apply before it closes?

Usually the biggest problem with chokes are the linkage binding up, or there is a build up of varnish on the choke housing or linkage. Often a good cleaning with a can of spray choke and carb cleaner does wonders.

Next up would be incorrect adjustments. There should be an adjustment on the choke housing for richer or leaner, there should also be a choke pull off the opens the choke a little after the motor fires, and there should be linkage to the throttle that will open the choke if the throttle is pushed to wide open. Any one or combination of these things being out of adjustment can cause a problem with the choke closing. Start with the cleaning first. Gene