I've encountered two different problems that might be relevant with a Yardman HE 5135 Ride-on Tractor. First problem was electrical - I forget the details, but basically I had a short (worn wire touching earth) in the cutter deck wire feed that switches in when the deck is engaged. This dropped the voltage to the ignition down to zero (i.e. engine stopped). I had to disconnect faulty wire and bypass it. Second problem was the very simple one of debris in the fuel tank getting stuck in the fuel line filter and starving the engine of fuel - the engine cut out when the extra load of the cutter deck was brought in. Solution: clean the fuel filter and remove any other debris upstream of it!