Simplicity Sunstar 18 h.p. tractor with mower deck. Hydro works nice - has little or no creep. Power steering works great. I recently had the mower deck off, cleaned, wire wheeled, primer'd, painted, sharpened the blades, and greased. Mower deck is solid and has no rust or holes. Deck raises and lowers smoothly. Cuts really nice - see pic's. Tractor starts immediately and runs well at slower RPM. Tractor has plenty of power to cut tall grass even at 1/2 motor speed. When running at high RPM, motor has a miss. When I pull the plug wire off on the Right side, motor will stay running. If I pull the plug wire off on the Left side, motor will stall. Compression is even on both sides. Tractor runs and cuts grass just fine at slower RPM. I have the mower deck covers. We adjusted the carb and put in new spark plugs. Not sure what the issue is???