91351-MG7-003 O-Ring (20.8X2.4) - Overview. The 91351-MG7-003 O-Ring (20.8X2.4) is a precisely engineered sealing component crucial for Honda marine engine systems. This part supports the fuel and mechanical systems by providing a reliable seal that prevents fluid leaks and contamination. Made to exact factory specifications, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. The O-Ring measures 20.8mm in outer diameter and 2.4mm i