Polaris Sportsman 400 Service Manual page 157

PILOT (IDLE AND SLOW) SYSTEM
This system supplies fuel during engine
operation with throttle valve closed (1) or
slightly opened. The fuel from float cham-
ber (2) is metered by pilot jet (3) where it
mixes with air coming in through pilot air
jet (4). The mixture then goes up through
pilot passage to pilot screw (5). A part of
the mixture is discharged into the main
bore out of bypass ports (6). The remain-
der is then metered by pilot screw and dis-
charged into the main bore through pilot
outlet (7).
STARTER SYSTEM (CHOKE OR ENRICHMENT)
When the choke cable (1) is activated, the
starter plunger (5) is lifted off the seat.
Fuel is drawn into the starter circuit from
the float chamber (2) through the starter
jet (3). Starter jet meters this fuel, which
then flows into starter pipe (4) and mixes
with the air (7) coming from the float
chamber. The mixture, rich in fuel con-
tent, reaches starter plunger and mixes
again with the air coming through a pas-
sage (8) extending from underneath the
diaphragm. The rich fuel/air mixture for
starting is discharged through starter out-
let (6) in the the main bore.
- projex@inbox.lv -
FUEL SYSTEM/CARBURETION
4
1
6
7
5
2
3
7
3
8
5
1
6
4
2
4.7