4.4
CARBURETION SYSTEM
SPECIAL TOOLS
CARBURETOR JETTING
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 “Jetting Chart” in
Chapter 1.
4. Clutching changes may also be required for changes in
elevation. Refer to the “Clutching Chart” in Chapter 1 for
recommendations.
Jetting Guidelines
Changes in altitude and temperature affect air density, which is
essentially the amount of oxygen available for combustion. In
low elevations and cold temperatures, the air is more dense and
has more oxygen. In higher elevations and higher temperatures,
the air is less dense with reduced oxygen.
Polaris Carburetors are calibrated for an altitude of 0-6000 ft. (0-
1800 meters) and ambient temperatures between +40 and +80°
F (+5° to +26° C). Carburetors must be re-calibrated if operated
outside this temperature and/or altitude range. The jetting
installed in production is not intended for all altitudes and/or
temperatures. In addition, air screw / pilot screw adjustments
and PVT adjustments may be required to suit operating
conditions.
Mikuni Jet Part Numbers
Main Jets Pilot Jets
Jet Number
Part Number Jet Number Part Number
112.5 3130554 40.0 3130624
115 3130555 42.5 3130526
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
PART NUMBER TOOL DESCRIPTION
2870975
Mity Vac
TM
Pressure Test Tool
2872314 Carburetor Float Adjustment Tool
WARNING
Gasoline is extremely flammable and
explosive under certain conditions.
Always stop the engine and refuel
outdoors or in a well ventilated area.
Do not overfill the tank. The tank is at full
capacity when the fuel reaches the bottom
of the filler neck. Leave room for
expansion of fuel.
Never start the engine or let it run in an
enclosed area. Gasoline powered engine
exhaust fumes are poisonous and can
cause loss of consciousness and death in
a short time.
Never drain the float bowl when the
engine is hot. Severe burns may result.
Do not smoke or allow open flames or
sparks in or near the area where refueling
is performed or where gasoline is stored.
If you get gasoline in your eyes or if you
should swallow gasoline, seek medical
attention immediately.
If you spill gasoline on your skin or
clothing, immediately wash with soap and
water and change clothing.
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
specifications or in the Owner’s Safety and
Maintenance Manual for each particular model.
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