90131-ZW4-000 Drain (12X15) Bolt - Overview. The 90131-ZW4-000 Drain (12X15) Bolt is an essential component in Honda marine engine systems. Designed specifically as a drain plug bolt, it plays a crucial role in securely sealing drain ports to prevent leaks and maintain reliable engine function. This bolt, measuring 12x15, ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. OEM Genuine Honda part designed to meet factory specifications