I have had this 1981 682 KT17 for many years and it has always had this miss or stumble at all rpm's. It will run smooth for a while and then sorta miss as a stumble and then go back to running smooth again. New points, condenser, coil, spark plug wires, carb overhaul, fuel pump etc. It will flood easy if you use the choke to start it too. Just thought some of you may know or have had this issue before. Tractor works great other than this slight miss or stumble.