Yamaha - Fuel Pump Assembly Fuel Delivery System 6C5-13910-10-00. Overview. When a Yamaha outboard starts hesitating or struggling under load, the fuel pump is often the first place experienced mechanics look. The Yamaha Fuel Pump Assembly 6C5-13910-10-00 is designed to keep fuel moving consistently from the tank to the engine so the motor can run smoothly across the entire throttle range. Over time, diaphragms and internal check valves wear down from heat, vibration, and modern fuels. Replacing