17620-ZV4-A21 Fuel Filler Cap - Overview. The 17620-ZV4-A21 Fuel Filler Cap is an essential component for Honda marine engine systems. It serves the primary role of securely sealing the fuel tank opening, preventing fuel leakage and contamination, which is crucial for the reliable operation of your marine engine. Designed to fit seamlessly with Honda marine fuel systems, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. This fuel