Yamaha - Nozzle Piece Jet Pump Steering Component YF1-68515-36-10. Overview. When you're running a Yamaha jet setup, the nozzle is what really translates engine power into control on the water. I've seen worn or damaged nozzle pieces make steering feel loose or reduce how responsive the boat or WaveRunner is. The Yamaha Nozzle Piece YF1-68515-36-10 helps direct water flow cleanly out of the pump so you get solid thrust and predictable handling. It's one of those parts that makes a big difference