19300-881-741 Thermostat Assembly - Overview. The 19300-881-741 Thermostat Assembly is an essential component in Honda marine engine cooling systems. Its primary role is to regulate the engine temperature, ensuring that the marine engine operates within an optimal temperature range for reliable performance and durability. This thermostat assembly belongs to the cooling system category, supporting steadfast temperature control necessary for preventing overheating or excessive cooling.. Key Featur