Polaris 340 Classic - Manual (Page 67)

65
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.
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.
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.
Improper carburetor adjustments may result in operator safety
hazards as well as serious engine damage. Always have your
Polaris dealer perform any carburetor adjustments.
WARNING
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.