90506-ZVD-000 Plain (6mm) Washer - Overview. The 90506-ZVD-000 Plain (6mm) Washer is a genuine OEM component specially designed for Honda marine engine systems. This plain washer supports various mechanical assemblies by evenly distributing the load of tightened fasteners, preventing damage to components and ensuring system integrity. Its role is crucial in maintaining the reliability and longevity of Honda marine equipment, providing a simple yet vital function that supports secure and durable