Fuel Delivery; Vent System; Carburetor Service; Carburetor Float Bowl Draining - Polaris PREDATOR 50 2009 Manual

Fuel Delivery

The throttle opening chart below demonstrates component
relationship to fuel flow versus throttle valve opening.
The pilot system's main function is that of a low speed jet. Its
most effective range of fuel delivery is from idle to
approximately 3/8 throttle valve opening.
The throttle slide controls the rate of engine air by its movement
up and down in the carburetor venturi. At small throttle openings
the air flow is regulated chiefly by the valve cutaway, with
greatest effectiveness at 1/4 throttle opening. Throttle valves are
numbered 1.0, 1.5, 2.0, etc., according to the size of the cutaway.
Decreasing the cutaway number will increase the amount of fuel
delivered in its effective range.
The jet needle and needle jet have an effective operating range
from approximately 1/8 to 7/8 throttle opening. The amount of
fuel delivered during this range relies upon the jet needle clip
position, as well as the needle jet size and other specifications.
The main jet affects fuel delivery at 1/4 throttle and consistently
increases to full throttle opening.
THROTTLE OPENING - Theory
EFFECT
Throttle Valve Cut-Away
Jet Needle/Needle Jet

Vent System

The fuel tank vent supplies atmospheric pressure to the fuel in
the tank. The vent must be free of debris and restrictions to
prevent lean mixture and possible engine damage. All vent lines
must be properly routed to prevent damage to the line and to
prevent contaminants from entering the tank.

CARBURETOR SERVICE

Carburetor Float Bowl Draining

The carburetor float bowl should be drained periodically to
remove moisture or sediment from the bowl, or before extended
periods of storage.
NOTE: Drain screw is located on the side of the
float bowl.
1. Place a clean container beneath the bowl drain spigot or
bowl drain hose.
2. Turn the fuel valve to "OFF".
3. Loosen drain screw and allow fuel in the float bowl and fuel
line to drain completely.
4. Inspect the drained fuel for water or sediment.
5. Tighten drain screw.
6. Turn fuel valve to "ON".
7. Inspect carburetor for fuel leaks
8. Start machine and re-check for leaks.
FUEL SYSTEM
Carburetor Bowl
Drain Screw
OFF
ON
4.9
4