16066-ZZ5-003 O-RING - Overview. The 16066-ZZ5-003 O-Ring is an essential sealing component within Honda marine engine fuel systems. Its primary role is to create a watertight seal that prevents fuel and vapor leaks, ensuring the engine operates smoothly and efficiently. As a genuine Honda OEM part, this O-ring is manufactured to meet strict factory dimensions and tolerances, providing a perfect fit and reliable operation in demanding marine environments. Designed to integrate seamlessly with Ho