56170-ZW4-H12 Manual Valve - Overview. The 56170-ZW4-H12 Manual Valve is an essential part of Honda marine engine systems, supporting the fuel or steering system to ensure reliable operation. This valve controls the manual operation within the system, playing a vital role in maintaining proper function and safety performance. Engineered as an OEM component, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Genuine Honda OEM Manual