Anonymous asked this question on 5/7/2000:

what causes a boat motor to run hot

CaptJohn gave this response on 5/7/2000:

Usually 1 of 2 reasons, that could make an engine run hot. BTW there are more than 2 reasons, but these are the most common. 1. the water pump, or impeller is worn out. This part is in the lower unit of an outboard. 2. either the oil/gas mixture is wrong or there is NO oil in the gas, that would be due to a faulty VRO, if you dont have to premix the fuel. 3. Bad head gasket, this will cause it to blow up usually., not run hot. 4. Warped head, if work was done and the head was not milled. Same thing, [usally blows up]