Polaris 9919078 - Manual (Page 70)

67
OPERATION
Carburetion
Proper carburetor adjustment is critical. A lean mixture (too much air,
too little fuel) may result in piston burning, bearing failure, or
complete engine failure. A rich mixture (too much fuel, too little air)
may foul plugs and cause generally poor engine performance.
A lean mixture may be caused by things like fuel line restrictions,
foreign matter in the carburetor or clogged fuel filters. A rich mixture
may be caused by snow build-up on the pre-filter in the air intake
system. Either condition may be caused by improper carburetor
adjustment.
WARNING
Improper carburetor adjustments may result in operator safety
hazards as well as serious engine damage. Always have your
Polaris dealer perform any carburetor adjustments.
Jetting Guidelines
Changes in altitude and temperature affect air density, which is 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 most Polaris models are calibrated for an altitude of
0-2000 ft. (0-600 meters) and ambient temperatures between -10 to +10
F. (-23 to -12 C.). All carburetors must be re-calibrated if operated
outside this range. The main jet installed in production is not correct
for all altitudes and/or temperatures.
CAUTION
A main jet that’s 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 your Owner’s Manual Supplement.
NOTE: Always ensure that the correct jets are installed in the
machine for your geographical area. Use care when jetting
down in warm weather. As the weather turns colder you
must re-jet upward to prevent engine damage. When
selecting the proper main jet, always use the lowest elevation
and temperature likely to be encountered.