91304-ZV5-821 O-Ring (1.5X6.5) - Overview. The 91304-ZV5-821 O-Ring (1.5X6.5) is a precision-engineered sealing component essential for Honda marine engine systems. It functions primarily within the sealing system to prevent fluid leaks, maintaining system integrity and engine reliability. Crafted to exact Honda specifications, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Genuine OEM Honda O-Ring with dimensions 1.5 mm inner