1992-1998 Polaris Personal Watercraft Service Manual PN 9912201, Page 173Get this manual

1992-1998 Polaris Personal Watercraft Service Manual PN 9912201, Page 173

FUEL SYSTEMCARBURETION System Operation Mikuni Carburetor Carburetor System Operation, 1992 to Current Pop Off Pressure Carburetor
of the valve is controlled by regulator diaphragm movement and spring pressure under the control armThe regulator diaphragm
is sealed to the carburetor body forming two chambersOne side is vented to atmospheric pressure, the other side (fuel chamber)
is connected to the venturi via the jets and passagesAtmospheric pressure pushes on one side of the diaphragm, applying pressure
on the control arm in the fuel chamberThis reduces pressure on the inlet needle and allows it to lift more easily off the
seatWhen the engine is running, pressure in the carburetor venturi (and therefore the fuel chamber) is less than atmosphericThis
increases the effect of the atmospheric pressure on the diaphragm and leverWhen return spring pressure is overcome by these
forces, the needle lifts off of the seat or "pops off', allowing pressurized fuel to enter the fuel chamberRegulator Diaphragm