Float System; Pilot Jet; Pilot Mixture Screw - Polaris PREDATOR 50 2009 Manual

FUEL SYSTEM

Float System

The float system is designed to maintain a constant height of
gasoline during operation. When the fuel flowing from the fuel
pump into the float chamber through the needle valve reaches
the constant fuel level, the floats rise. When the buoyancy of the
float and the fuel pressure of the fuel pump balance, the needle
valve seals the orifice in the needle seat, preventing further fuel
delivery, and the level of fuel in the bowl remains relatively
constant.
The fuel level in the bowl assists in controlling the amount of
fuel in the fuel mixture. Too high a level allows more fuel than
necessary to leave the nozzle, enriching the mixture. Too low a
level results in a leaner mixture, since not enough fuel leaves the
nozzle. Therefore, the predetermined fuel level should not be
changed arbitrarily.

Pilot Jet

From idling to low speeds, the fuel supply is metered by the pilot
jet. There are several air bleed openings in the sides of the pilot
jet which reduce the fuel to mist. The number stamped on the jet
is an indication of the amount of fuel in cc's which passes
through the jet during a one minute interval under a given set of
conditions.
4.4

Pilot Mixture Screw

The pilot mixture screw controls the fuel mixture from idle to
low speeds. The tapered tip of the mixture screw projects into
the fuel mixture passage leading to the pilot jet air bleeds. By
turning the screw in or out, the cross sectional area of the air
passage is varied, in turn varying the pilot jet air supply and
changing the mixture ratio.
Pilot Jet
Number
CAUTION
The pilot air screw is calibrated at the factory to
meet EPA / CARB regulations for air quality
standards. Cleaning of the pilot circuit must be
performed by a certified repair shop to ensure
air quality standards are not exceeded.
Pilot Screw
Pilot Screw
90cc Keihin
50cc Mikuni