Carburetor Jetting; Cv Carburetor System Function (4 Cycle); Pilot Screw; Mikuni Jet Part Numbers - Polaris 2009 Trail Boss 330 Service Manual

FUEL SYSTEM/CARBURETION
/ pilot screw adjustments and PVT adjustments may
be required to suit operating conditions.

CARBURETOR JETTING

CAUTION:
A main jet that is too small will cause a lean
operating condition resulting in serious engine
damage. Select the correct main jet carefully for
elevation and temperature according to the
charts in the Specifications section or in the
Owner's Safety and Maintenance Manual for each
particular model.
IMPORTANT: The following guidelines must be
followed when establishing a main jet setting:
1. Select the lowest anticipated temperature at
which the machine will be operated.
2. Determine the lowest approximate altitude at
which the machine will be operated.
3. Select the correct main jet from the chart on page
on the Specifications page.
4. Clutching changes may also be required for
changes in elevation. Refer to clutching chart in
the Specifications section for recommendations.

MIKUNI JET PART NUMBERS

Main Jets
Jet Number Part Number
112.5 3130554
115 3130555
117.5 3130556
120 3130557
122.5 3130558
125 3130559
127.5 3130560
130 3130561
132.5 3130562
135 3130563
137.5 3130564
140 3130527
142.5 3130566
145 3130567
147.5 3130568
150 3130569
152.5 3130570
155 3130571
157.5 3130572
160 3131141
162.5 3131142
165 3131143
167.5 3131144
170 3131145
4.6
Pilot Jets
Jet Number Part Number
40.0 3130624
42.5 3130526
50.0 3131132
CV CARBURETOR SYSTEM
FUNCTION
Carburetor Component Function
System Main
Components
Float Inlet Pipe,
System Needle and
Seat, Float,
(Level Control)
Float Pin
Venting Passages in
Carburetor,
Vent lines
to frame
Starter Choke Lever,
(Choke/En- Cable, Plung-
richment) er, Return
Spring, Carb
Passages
(Starter Jet,
Starter Bleed
Pipe)
Pilot Pilot Jet/
(Idle System) Passage-
ways, Pilot-
Mixture
Screw with
Spring
Washer and
Sealing O-
Ring, By-
pass Ports
(Behind
Throttle
Plate), Pilot
Air Jet, Pilot
Outlet,
Throttle
Plate
Main Main Jet,
System Main Air Jet,
Main Air
Passage,
Needle Jet,
Jet Needle,
Vacuum
Slide,
Throttle
Plate
Main Main
Function Affect
Maintains All systems
specified All throttle
fuel level in ranges
float cham-
ber (carbu-
retor float
bowl)
Supplies All systems
atmospheric All throttle
pressure to ranges
float cham-
ber
Supplies All throttle
additional ranges
fuel air mix- Greatest
ture neces- effect at
sary for cold low throttle
starting settings
and idle
Primarily Mainly idle
supplies fuel to 1/4
at idle and throttle
low throttle Minimal ef-
positions fect after
1/2 throttle
Supplies 1/4 to full
fuel at mid- throttle
range and
high throttle
settings.