Overheating has got to be one of the most common ways a marine engine bites the dust. Lack of maintenance is probably the main culprit. Impellers, hoses, hose clamps, water
pump belts and circulating
pumps can all fail and it doesn't take very long to cause damage if at high rpm. Mostly a matter of maintenance to prevent failures and just using the good old eyeball on a regular basis to look things over. The
alarms that warn of a lack of raw water seem like a good idea, although I haven't installed one yet.