16957-ZE1-811 Petcock Gasket - Overview. The 16957-ZE1-811 Petcock Gasket is a crucial component designed for Honda marine engine systems. It plays a vital role in the fuel system by creating a reliable seal for the petcock valve, preventing fuel leaks and ensuring proper fuel flow and engine operation. This gasket offers a seamless fit with original equipment, maintaining fuel system integrity, durability, and performance.. Key Features. Precision-engineered gasket for the fuel petcock valve to