90531-ZVA-000 Gear Washer - Overview. The 90531-ZVA-000 Gear Washer is a critical component in Honda marine engine systems, specifically designed to support the gear mechanism within the engine's assembly. It plays a vital role in maintaining reliable operation of the gear system by providing precise spacing and alignment of gears, which is essential for smooth mechanical motion and durability.. Key Features. Genuine OEM Honda part, ensuring exact matches to factory specifications and dimensions