90502-ZW5-U00 Washer Lock (6mm) - Overview. The 90502-ZW5-U00 Washer Lock (6mm) is a precision-engineered lock washer designed specifically for Honda marine engine systems. It plays a critical role in ensuring that fastened components remain secure under the harsh conditions typical of marine environments. By preventing loosening caused by vibration, this lock washer supports the reliable operation and longevity of Honda marine equipment. Crafted to meet exact factory specifications and dimensio