Polaris 440 IQ Owner's Manual page 57

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.
54