I have a Cub cadet zero turn FH680VA23705 23horsepower 60 inch deck (490) on the hours. When I goto engage my blades my rpms drop a lil but when I move foward it dies down more. Now it won't start turns over but no start. Full charge on battery, checked oil, checked the fuse. It gets gas to carb but no spark. I checked all kill switches and, all seem fine. As long as it turns over could it still be a kill switch. Any help would be great please!