If repairing flimsy choke with a spring does not help, check the slide for proper assembly as well as the needle clip position. Alot of the Chinese instructions tell you to put the silver notched washer inside the slide first, underneath the needle and clip. This is wrong. It needs to go above the needle and clip. If the silver notched washer is installed underneath, the needle can get hung up and not move with the slide like it is supposed to.
This will enrichen the mixture as if the choke is on and yes, the engine can bog out.