Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Hi Bernard, my name is***** will be assisting you.
This sounds like the ignition coil is going bad. It allows for the machine to run until it gets hot and then it quits firing to the spark plug. To easily check this you can run the machine up to the point that it quits and then check the spark coming to your plug.
Check it out and let me know what you find.