91318-ZV5-821 O-Ring (2.0X55.5) - Overview. The 91318-ZV5-821 O-Ring (2.0X55.5) is a precise sealing component used within Honda marine engine systems, playing a vital role in maintaining water-tight connections and preventing leaks. Designed specifically for Honda engines, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. 2.0mm thickness and 55.5mm diameter O-ring for reliable sealing in fuel, cooling, or hydraulic systems.. Genuine OEM Honda part, ensuring factory-level specifications and quality.. Manufactured to exact dimensions and tolerances specified by Honda for consistent performance.. Enhances system reliability by preventing fluid leaks and contamination.. Designed to integrate cleanly with OEM hardware, gaskets, or housings.. Maintains expected durability and performance typical of Honda marine parts.. Why Choose Genuine OEM. Using original Honda parts like the 91318-ZV5-821 O-Ring preserves the integrity of