2001 Polaris SLX, PRO 1200, Virage TX, Genesis, Virage TXi, Genesis i Personal Watercraft Service Manual, Page 175Get this manual
CarburetionExhaust 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 III1III1 Piston on upstroke Inlet check valve open Outlet check valve closed