My son has a Grizzly 80 with carburetor issues. The carb has been cleaned very well but still has a problem with the idle hanging. There are no air leaks, at least none that can be found with propane around the carb and intake. This in a small makuni carb with the throttle cable connected directly to the slide, i.e. there is no butterfly valve. The slide moves freely and both the slide and carb chamber are spotless. The idle speed adjustment screw comes in from the side of the carb and makes contact with a beveled slot on the bottom of the slide.

The engine starts easily, and initially idles correctly. However, when the throttle is opened and closed the idle hangs initially, but if left running it will eventually settle down. The throttle cable is clean and oiled and there are no kinks. After having worked on this several times, I am of the opinion that the fact that the idle adjustment screw comes in from the side is causing the slide to bind within the slide chamber and I don't know of any cure for this if it is what is happening. The adjustment screw has no imprefections and the beveled slot looks to be perfect.

Before I buy a new carburetor, does anyone have any experience with this problem and any suggestions?