Try this

remove the air filter
back off the idle adjustment screw
close the carburetor
slowly turn in the idle adjustment screw until the carburetor starts to open
when it's open about 1 mm, stop

If it tightens against the barrel and the barrel doesn't rotate open at all, try moving the barrel (wiggle it in and out a little so the idle adjustment screw locates the groove the the carb barrel


Good luck