I have had overheating problems when attempting to running the A4 for the first time in the spring, having drained it after the previous liftout. What seems to happen is that water bypasses the engine because the thermostat is closed, hence the overheating. Running it at low speed clears the problem eventually because the thermostat does not provide a perfect seal. I believe that a better solution is (1) keep the raw water shutoff valve closed until the boat is in the water, and (2) fill the engine with water through the thermostat housing prior to lift-in. Hope that this helps.