19315-ZY9-M00 Thermostat Cover - Overview. The 19315-ZY9-M00 Thermostat Cover is a vital component in Honda marine engine systems. It supports the engine's cooling system by housing and protecting the thermostat, ensuring efficient temperature regulation to prevent overheating. This cover is engineered to fit Honda marine engines precisely, offering seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. OEM genuine thermostat cover designed speci