16400-ZVL-003 Throttle Body - Overview. The 16400-ZVL-003 Throttle Body is an essential component of the fuel and air delivery system in Honda marine engine systems. It precisely controls the amount of air entering the engine to help regulate power output and responsiveness, ensuring smooth and reliable operation on the water. Designed to meet exact factory specifications, it integrates seamlessly with existing engine hardware to maintain peak performance and durability.. Key Features. Electroni