16957-ZE1-812 Petcock Gasket - Overview. The 16957-ZE1-812 Petcock Gasket is a vital component in Honda marine engine systems, designed to support the fuel system specifically at the petcock valve assembly. Its primary role is to create a reliable seal that prevents fuel leaks and ensures smooth fuel flow to the engine, thereby maintaining optimal engine performance and reliability. Crafted to exact OEM specifications, it ensures seamless integration with existing parts, maintaining optimal perf