15236-ZY9-M01 Sealing (18mm) Bolt - Overview. The 15236-ZY9-M01 Sealing (18mm) Bolt is a vital component in Honda marine engine systems. It functions primarily to create a secure and watertight seal, ensuring the protection and integrity of the engine's internal components from water ingress and pressure leaks. Designed to exact factory specifications, this sealing bolt facilitates seamless integration within the marine engine assembly, maintaining optimal performance and durability under demand