Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 173Get this manual
Air Pressure Regulator Regulator Closed Regulator Open
1Top CoverExpansion PlugSpring RetainerVentSpringDiaphragm SeatAir RailAir Passage (from Air Compressor)Excess Air Passage (to Exhaust Adaptor) 10- Fuel Inlet Passage (from Electric Fuel Pump) 11- Diagram Assembly 12- Calibration Screw (Do Not Turn)
The air pressure regulator is designed to limit the air pressure inside the rails to approximately 80 psiThe air regulator uses spring (pressure) to control the air pressureThis spring (80 psi) holds the diaphragm against the diaphragm seatThe contact area blocks (closes) the air inlet passage from the excess air, return passageAs the air pressure rises (below the diaphragm), it must reach pressure equal to or greater than the spring pressure holding the diaphragm closedOnce this pressure is