I have a JOHN DEERE LX176 with a 14hp Kawasaki engine that i bought new 11 years ago. Lately im having a problem. The tractor starts right up and i can mow my lawn but if i shut it off it wont restart. It only has to run for 5-10 minutes and it wont restart for an hour or so. (cooling off i guess). Ive replaced the oil and filter, air and fuel filters, spark plug, fuel line and cleaned out the gas tank. Ive also sprayed gumout into the carb. Any ideas?