Fuel System/Carburetion - 1996 Specifications; Jetting Guidelines; Jetting Compensation For Altitude And Temperature - 1996 Models - Polaris Magnum 2x4 Service Manual

FUEL SYSTEM/CARBURETION
1996 Specifications
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 has more oxygen. In higher elevations and higher
temperatures, the air is less dense.
Carburetors on Polaris ATVs are calibrated for an altitude of 0-3000 ft. (0-900 meters) and ambient temperatures
between +40 and +80° F (+5° to +26° C). All carburetors must be re-calibrated if operated outside the production
temperature and/or altitude range. The main jet installed in production is not correct for all operating conditions.
A main jet that is too small will cause a lean operating condition and may cause serious engine damage.
Jet the carburetors carefully for elevation and temperature according to the jetting charts in this chapter,
or in the Owner's Safety and Maintenance Manual for each model.
NOTE: Maximum engine efficiency and horsepower are directly related to proper carburetor settings. The follow-
ing charts have been established as a guideline for selecting optimum jetting for varying temperature and altitude
conditions. Air screw or fuel screw adjustment will affect mixture from approximately 0 to 1/4 throttle setting and
should be adjusted as follows:
Air Screw (2 stroke models)
Turn the air screw in (clockwise) 1/4 turn for each 30° below 60° F. Turn the air screw out (counterclockwise) 1/4
turn for each 30° above 60°
F.
Fuel Screw (4 stroke models)
Turn the fuel screw in (clockwise) 1/4 turn for each 30° above 60° F. Turn the fuel screw out (counterclockwise)
1/4 turn for each 30° below 60° F.
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. Tracing down and across on the chart, use the intersecting main jet recommendation.
4. Clutching changes may also be required for changes in elevation. Refer to clutching charts in Chapter 6 for
recommendations.
Jetting Compensation for Altitude and Temperature - 1996 Models
Trail Blazer
AMBIENT TEMPERATURE
Production Jetting Specifications
Below
0° to +40°F +40
0
to +80°F +80
0 &
O°F -18°to +5°C +5' to +2S·C
Above OF
Carburetor Type ........ Mikuni VM30SS
Below 26°
&
·18·C Above °C
0-900 150 140
130 120
Main Jet 130
(0-3000)
Pilot Jet 40
900-1800 140 130 120 110
Jet Needle 5DP7-3
Altitude (3000-S000)
Needle Jet 0-4 (169)
Meters
Cut Away 2.0
(Feet)
1800-2700
125 120
110 100
(SOOO-9000)
Air Screw 1 Turn
2700-3700 115 110 100 95
(9000-12000)
Polaris Industries Inc. 4.1
5/98