Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Sudden overheat? Take thermostat out at top connection on the engine, and with it removed and open, crank engine to see if the coolant flows out! If it does not, the water pump has failed. If water pours out, water pump is good. But you may want to get a heat temperature gun (Harbor Freight) and check the unit to be sure it is overheating. The sender can always be defective.
Can you find the long model number for the Tank. example 51A345m35, then I can find the exact setup of engine.