2002 Polaris Freedom, Virage, Genesis PWC Service Manual, Page 175Get this manual
FuelExhaust Fuel Pump Operation
The pump supplies fuel to carburetorsOn three cylinder models two fuel pumps supply fuel to each of the end carburetors and commonly to the center cylinderWhen the piston is on the upstroke crankcase pressure is low, the diaphragm in the fuel chamber moves outward toward the chamber coverThis causes negative (low) pressure in the fuel chamberThe check valve on the fuel supply side of the chamber opens, allowing fuel to enterThis vacuum causes the outlet check valve to close so fuel cannot return from the carburetorSee Ill1Ill1 Piston on upstroke Negative (low) crankcase pressure Inlet check valve open Outlet check valve closed Fuel return to tank