Quicksilver - Fuel Pressure Regulator MerCruiser MPI Series Precision Fuel Control 861126A1. Overview. Every boater knows the feeling of a perfectly tuned engine - that crisp throttle response, that steady push as the boat climbs onto plane. When the fuel system is balanced, everything feels smoother. This Quicksilver fuel pressure regulator is one of those behind-the-scenes parts that quietly keeps the engine behaving its best. It's the kind of component you trust without thinking about it, bec