16400-ZZ3-003 Throttle Body Assembly - Overview. The 16400-ZZ3-003 Throttle Body Assembly is a critical component within Honda marine engine systems. It controls the airflow into the engine, which directly influences engine speed and power output, ensuring smooth and efficient operation. Designed specifically for Honda outboard motors, this throttle body assembly guarantees seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. OEM throttle body