Stihl blower wont idle but runs perfect wide open, why?

I have a bg55 stihl blower that is 6-8 yrs old and it wont idle nor run while a half speed, but will run all day long on high, wide open. I tried spraying carb cleaner into the carb also pulled the low speed adj screw out and flushed it w cleaner, then reinstalled by lightly seating then backing out 1'turn per the manual. These efforts made no difference whatsoever.



I am trying to avoid a complete carb rebuild or replacement if possible but perhaps that is my only option. Any ideas? Thank you