2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 21Get this manual
MAINTENANCE Carburetor Draining
The carburetor float bowl should be drained periodically to remove moisture or sediment from the bowl, or before extended periods of storageNOTE: The bowl drain screw is located on the bottom left side of the float bowl123Turn fuel valve to the "OFF" position (see "Fuel Valve" for location)Place clean container beneath the float bowl drain spigot or float bowl drain hoseTurn drain screw out two turns and allow fuel in the float bowl and fuel line to drain completely
Pilot Screw Location
The pilot system supplies fuel during engine operation with the throttle valve closed or slightly openedThe fuelair mixture is metered by pilot screw and discharged into the main bore through the pilot outlet