90242-MB0-000 lock (64mm) nut - Overview. The 90242-MB0-000 lock (64mm) nut is an essential component designed specifically for Honda marine engine systems. This locking nut with a 64mm diameter plays a crucial role in securing critical parts within the marine engine system, ensuring seamless integration with existing parts and maintaining optimal performance and durability. Its precise engineering guarantees it meets factory specifications, dimensions, and tolerances.. Key Features. This lockin