Thermostat Kit (140°F/60°C) – Fits MerCruiser 2.5L & 3.0L Stern Drives (Replaces 59078Q3, 18-3650) family-yamaha-4sk Replace the belt if you

Replace the belt if you notice cracks

It ensures proper engine temperature regulation for reliable performance across a wide range of applications including jet models and commercial units

Reconnect the fuel lines to the correct ports on the new filter

Start the engine in a test tank or on-water and verify strong water flow from the telltale (pee hole)

Replacement intervals depend on engine hours and operating conditions

Thermostat Kit (140°F/60°C) – Fits MerCruiser 2.5L & 3.0L Stern Drives (Replaces 59078Q3, 18-3650) family-yamaha-4sk Replace the belt if youThermostat Kit (140F 60C) Fits MerCruiser 2. 5L & 3. 0L Stern Drives This thermostat kit is designed for MerCruiser 2. 5L (120HP) and 3. 0L (140HP) inline 4 cylinder and 6 cylinder GM engines (1998 and newer) equipped with cast iron exhaust manifolds. It serves as a direct replacement component for maintaining optimal engine operating temperature. Engineered to match OEM specifications, this kit directly replaces MerCruiser part numbers 59078Q3,