2005-2007 Polaris Ranger 500 service manual, Page 116Get this manual
CARBURETION SYSTEM Main System
As throttle valve (1) is opened, engine speed rises, and this increases negative pressure in the venturiConsequently the vacuum slide (2) moves upwardThe fuel in float chamber (3) is metered by main jet (4), and the metered fuel enters needle jet (5), in which it mixes with the air admitted through main air jet (6) to form an emulsionThe emulsified fuel then passes through the clearance between needle jet (5) and jet needle (7), and is discharged into the venturi (A)Mixture proportioning is accomplished in needle jet (5); the clearance through which the emulsified fuel must flow is determined ultimately by throttle position and vacuum slide height