Yamaha Fuel Cock Assembly 733-24500-20-00. Overview. The Yamaha Fuel Cock Assembly 733-24500-20-00 is a genuine original equipment manufacturer component designed to control the flow of fuel from the tank to the engine. This essential valve allows you to safely start, stop, or regulate fuel delivery, helping maintain efficient and reliable engine operation.. Built to Yamaha's exact specifications, this fuel cock assembly ensures a precise fit and dependable performance. It is an ideal replacemen