Pilot System (Idle - 3/8 Throttle); Slide Cutaway (1/8 - 3/8 Throttle) - Polaris PREDATOR 50 2009 Manual

Pilot System (Idle - 3/8 Throttle)

The pilot system's main function is to meter fuel at idle and low
speed driving. Though its main function is to supply fuel at low
speed, it does feed fuel continuously throughout the entire
operating range.
Fuel for the pilot jet is drawn from the float bowl, mixed with air
regulated by the air screw, and delivered to the engine through
the pilot outlet.
The mixture is regulated to some degree by adjusting the air
screw. When the air screw is closed, the fuel mixture is made
richer as the amount of air is reduced. When the air screw is
opened, the mixture is made more lean as the amount of air is
increased.
General Carburetor Representation
Main Jet
Throttle Valve
Throttle Stop
(Idle Speed)
Screw
By-
pass
Pilot
Outlet
Air Screw
Pilot Jet

Slide Cutaway (1/8 - 3/8 Throttle)

Throttle valve cutaway effect is most noticeable at 1/4 throttle
opening. The amount of cutaway is pre-determined for a given
engine to maintain a 14:1 air/fuel ratio at part throttle. A steep
angle would indicate a fairly lean mixture because there is less
resistance to air flow. A flat angle would provide a much richer
mixture because there is more resistance to air flow.
The venturi shape can be adjusted for each engine's breathing
characteristics by using a different valve cutaway angle. A
number will be stamped into the bottom of the valve (e.g. 2.5)
indicating the size of the cutaway. The higher the number, the
steeper the angle.
General Carburetor Representation
Cutaway Angle
Air Jet
Air Box
Side
FUEL SYSTEM
Throttle Valve
Jet Needle
By-pass
Pilot Outlet
Engine
Side
Pilot Jet
Needle Jet
Main Jet
4.7
4