2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 123Get this manual
CARBURATION AND FUEL SYSTEM When the pressure above and below the diaphragm are nearly equal, the slide moves downward under spring pressureRaising or lowering the slide increases or decreases the cross sectional area in the venturi, and therefore the air velocity in the venturi is kept relatively constantThis provides improved fuel atomization and optimum fuelair ratio
Carburetor Venting
The carburetor float bowl vent lines supply atmospheric pressure to the float bowlThe lines must be free of kinks, restrictions and be properly routedThis allows fuel to flow in the proper amount and prevents contaminants from entering the carburetor
Starter System (Choke or Enrichment)
When the choke cable (1) is activated, the starter plunger (5) is lifted off the seat8 5