I have a LazerZ 48". It's 14 years old. The other day the blades just quit turning (engine still going). The PTO was still out but nothing happening. The belts are all good. Started it the next day and the blades ran for about 15 minutes and quit. I waited a while and it did the same thing 3 more times. It works just fine while the blades turn. Any ideas would be appreciated.