YAMAHA THERMOSTAT 6E5-12411-30

Function and technical context

The thermostat regulates the operating temperature of the marine engine keeping the cooling flow in optimal balance. It is part of the water cooling system, controlling when the coolant circulates through the radiator or heat exchanger according to the instantaneous thermal needs of the engine. Its correct operation is critical: a defective thermostat causes overheating, loss of power, accelerated damage to cylinders and seals, or, on the contrary, keeps the engine at low temperatures during startup with consequences in fuel consumption and premature wear.

When to replace this part?

Typical symptoms include abnormal variations in the thermometer needle, excessive heating even at low rpm, or permanently low readings after starting. It is recommended to inspect and clean the thermostat every boating season, especially in waters with sediment or high salinity that encourage scale. Replacing the thermostat preventively before sailing in distant waters avoids breakdowns in compromised situations where access to spare parts is limited.

Equivalent manufacturer part numbers