90503-ZVT-000 Washer (15Mm) - Overview. The 90503-ZVT-000 Washer (15Mm) is a precision-engineered component vital to Honda marine engine systems. This 15mm washer functions primarily to distribute mechanical load evenly, which helps to reduce stress on adjoining parts and prevents damage during assembly and operation. It is designed specifically to fit within the rigging and accessory systems of Honda marine engines, providing reliable integration with existing hardware and mounting surfaces to