06/04/2017
A little known outboard part that can cost $7000 after three years. One of the least appreciated components of an outboard motor is the lowly thermostat. It is subject to constant temperature changes, corrosion, and water pressure along with mud, sand, and salt, yet is expected to last forever. If it fails, the thermostat can cause the complete failure of your power head and cost $7000-$8000 to replace. A regular annual maintenance plan that includes replacing your thermostats can prevent this expensive repair.
Often misguided individuals remove it from the motor thinking it is either not needed or to just get by when an overheat condition is caused by a different part of the engine. A thermostat regulates the temperature of the water for engine cooling and keeps pressure in the cooling system to facilitate heat transfer from the heads and the cylinder walls. Today’s engines are designed with little tolerance for incorrect temperature operation whether it is too hot or too cold. The emission regulations make the thermostat even more important for correct engine operation and depending how the laws are interpreted may put you in violation by removing it or substituting one with a different rating. Today's low-emission computer-controlled marine power plants are dependent on thorough combustion for reduced exhaust emissions. That is made possible by having the proper engine temperatures and fuel mixtures. Failure to have a properly operating thermostat has so many devastating effects, it is just better to service them regularly rather than take a chance with your motor.