[RCW]

It sounds like you may have a couple of issues.

The low end deadness is likely a carburetor problem with a plugged pilot circuit, or the pilot screw is set incorrectly, or the float level is incorrect. Some of these have a plastic block on the pilot screw to meet CARB emission standards. I pull that block and adjust the pilot to where they run good, then set the idle and fine tune the pilot circuit until it runs where I want.

On the idle, hold the carburetor throttle linkage fully closed on the idle stop and if the idle does not drop the problem is the carburetor. Loose throttle plate screws can keep the throttle from closing and create idle nightmares too. If the linkage will move and the idle drops, then the problem is the governor linkage or the foot throttle cable may be binding.

It would also not hurt to check your choke cable to be sure it is fully opening the choke.

The engine should idle down so low it will stop.

Some clutches do not fully release even at a very slow idle, and will continue to pull the belt over and cause the transmission to spin. That will result in grinding into gear. In that case and the clutch is good, and the belt is within specifications, then I adjust the distance between the drive and driven clutch units slightly closer so the belt quits pulling the secondary over. That will slow the Mule down a bit, but the difference between 23 and 25 mph is not that great for most people's use, and the drop in wear on the transmission is well worth the reduced speed.