what can cause an outboard to overheat
This means that a marine engine will overheat to extreme temperatures very quickly. An extreme overheat can warp the engine heads, crack manifolds, and do other serious permanent damage to the engine. So, if your engine overheat alarm goes off, shut it down as soon as possible. One, this will minimize any damage.
Thermostats regulate the temperature of the water in the cylinder block and help pressurize the system allowing rapid heat transfer from the cylinders to the cooling water. Most outboard motors use a similar system for cooling, regulating pressures, and maintaining correct engine temperatures. Water is drawn in through the gearcase inlet screens where it is then pumped up to the powerhead. It enters the bottom of the cylinder block and travels through passageways around the exhaust areas.