5.7 liter mercruiser.. My boat has a water heater that uses water from the engine to heat up the the water in the water heater.<br /><br />1. Would a boat that circulates water to the water heater run cooler or warmer than an engine that doesn't? <br /><br />2. If the water heater has a clog in it somewhere in this circulation, would it cause the engine to run warmer?