Yanmar Thermostat 128990-49800

The Yanmar thermostat, part number 128990-49800, fits multiple diesel marine engines and is calibrated to open at 71°C (160°F).

Like all engine thermostats, this component regulates engine temperature by managing the coolants' circulation.

When the engine is cold, the thermostat stays closed to block coolant flow, enabling the engine to quickly reach its optimal operating temperature. Upon reaching 71°C, the thermostat opens to permit coolant circulation, dissipating excess heat from the engine.

This Thermostat is compatible with:

• 2YM15
• 3YM20
• 3YM27A
• 3YM30
• 3YM30AE
• 3YM30R