2002 Polaris Freedom, Virage, Genesis PWC Service Manual, Page 145Get this manual

2002 Polaris Freedom, Virage, Genesis PWC Service Manual, Page 145

FuelExhaust Keihin Carburetor System Overview The Keihin carburetor is floatless diaphragm typeSeveral separate but overlapping
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 lever and overcomes spring pressureWhen the lever return spring pressure is overcome by these forces, the
needle lifts off of the seat or "pops off", allowing pressurized fuel from the fuel pump to enter the fuel chamberFuel inlet
needle "pop off" pressure is influenced by many factorsAtmospheric pressure, venturi low pressure, the amount of spring pressure
on the control arm, and fuel pressure from the fuel pump all have an affect on operating pop off pressureAll of these forces
combined regulate the amount of fuel that enters the carburetor fuel chamber and the engineChanges to pop-off pressure are
not recommended3Idle (Slow) System At idle and low throttle settings, fuel mixture is controlled by the idle mixture screw