91405-ZZ3-000 Flush Valve Tube - Overview. The 91405-ZZ3-000 Flush Valve Tube is a vital component designed for the Honda marine engine flushing system. It plays an essential role in enabling fresh water flushing of the engine to remove debris, salt, and other corrosive elements, thus extending the life and maintaining the reliability of your marine engine system. Engineered to Honda's factory specifications, this tube ensures seamless integration into existing rigging and hardware.. Key Feature