13310-ZN4-020 Crankshaft - Overview. The 13310-ZN4-020 Crankshaft is a vital component of Honda marine engine systems. This crankshaft converts the reciprocating motion of the pistons into rotational motion, powering the propeller for smooth and efficient operation. As a core part of the engine's mechanical system, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Genuine OEM Honda crankshaft designed specifically for Honda BF2D a