31116-ZW5-000 Flywheel Boss - Overview. The 31116-ZW5-000 Flywheel Boss is a key component in Honda marine engine systems. It serves as a precise mounting point connecting the flywheel to the engine's crankshaft, ensuring the transfer of rotational power essential for engine operation. Engineered to meet exact factory specifications, this essential part supports reliable and efficient engine performance. Designed for seamless integration, it maintains optimal performance and durability within Ho