It is a John Deere STX38 with a Kohler CV13 Engine. I can not get it to idle below 2200 rpm. I have adjusted the idle speed screw and idle mixture screw with no luck. I have also adjusted the governor (static) per the repair manual. There is some play in the throttle shaft but not that much IMO. The throttle shaft is resting against the idle screw as it should. I have had the carb off to check the throttle plate and it is there. I have even put an o'ring under the throttle shaft to make sure there was no air leak. I could really use some help on this one. I dont think a new carb will fix the problem -- do you folks ??