My ZT XL 52 won't stay running. It has 35 hours on it. It dies after mowing for an hour. Refuel and runs 30 minutes. Refuel runs 15 minutes. Changed the fuel filter as it acts like its running out of fuel. Now it runs until I move the arms to go forward and reverse. It starts trying to die. Shorted out the seat safety switch to test that. I'm also having trouble getting the parking brake to engage to let me try to restart the engine after dying. All this started after I change the oil. Could some of the oil leaked down on some hidden switch connected to the parking brake. Help. Thanks.