Yamaha - Thermostat Cartridge Insert Cooling System Component 61A-44322-02-00. Overview. Keeping the cooling system working properly is one of the most important parts of maintaining a Yamaha outboard. The Yamaha Thermostat Cartridge Insert 61A-44322-02-00 helps guide and support the thermostat assembly so the engine maintains stable operating temperatures. When these inserts wear or corrode over time, the thermostat may not seat correctly, which can affect how the engine regulates heat. Replaci