When I set up my carb I had the same problem you have.
you have to turn the choke more. you may not like that way ,but if you want your high idle to last it must be done. You need it in cold weather. Set your high idle 2000 RPM cold engine
I had to adjust the choke so much that the flap or buttery fly would be closed to much . I was so choked the motor would not start,know air could get in I solve this by taking a paper clip, a large one. I bent the clip so one side was in the carb to keep the flap from closing all the way the other side of the clip I mounted to one of the air cleaner hold down bolts , so it would stay there.
I know it sounds crazy but that is all I could do, I must have high idle in new York cold weather
It must be tested on cold engine if it is very cod out the flap will close to much and the engine will not start. The paper clip will keep the flap from closing all the way