Why is my Mercruiser overheating?

Answer by  Jaggers (1018)

Your Mercruiser has a pump to circulate water to keep your engine cool. If the pump is working properly then check the water jacket for blockages. If there are no obstructions in the water jacket try repeating these steps with the boat in the water. If you are still overheating move to a cooler climate.

Answer by  Zaka (2315)

It is not calibrated adequately, more likely than not. The Revolutions per minute (RPMs) tend to "stick" as the valves becomed heated.