Polaris 120 Youth - Manual (Page 58)

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ADULT SECTION
Maintenance
Carburetor
Proper carburetor adjustment is critical, since a mixture too lean (too
much air, too little fuel) will result in overheating of the combustion
chamber causing pre-ignition of the fuel. This results in piston burning,
bearing failure, or complete engine failure. A lean mixture can be the
result of fuel line restrictions, foreign matter in the carburetor, etc. A
mixture too rich (too much fuel, too little air) is also unfavorable
because it can foul plugs and cause generally poor engine performance.
All carburetors have been pre-set at the factory for adequate fuel supply.
Higher altitude operation may require different adjustment and settings.
The number stamped in the end of the main jet indicates the jet size that
was installed at the time of manufacture. For questions about optional
jetting for conditions in your area, see your Polaris dealer.
Correct setup provides engine RPM within its given power band at full
throttle settings and also provides maximum efficiency and operation at
all other throttle openings. See your dealer for carburetor adjustments,
which may include the following:
• Carburetor component changes for specific altitude and ambient tem-
peratures
• Choke adjustment
• Air screw settings (if applicable)
• Idle RPM adjustments
• Throttle safety switch inspections and service
• Throttle block-to-throttle flipper clearance adjustment
CAUTION
Improper carburetor adjustments can result in safety hazards as well as seri-
ous engine damage. We recommend that all carburetor adjustments be per-
formed by your Polaris dealer.