Snowmobile Polaris 120 PRO R (2013 year). Instruction - part 13

53

ADULT SECTION

Maintenance

Spark Plugs

Normal Plug
The normal insulator tip is gray, tan or light brown. There will be few 
combustion deposits. The electrodes are not burned or eroded. This indi-
cates the proper type and heat range for the engine and the service.

TIP: The tip should not be white. A white insulator tip indicates overheating, 

caused by use of an improper spark plug or incorrect carburetion adjust-
ments.

Wet Fouled Plug
The wet fouled insulator tip is black. A damp oil film covers the firing 
end. There may be a carbon layer over the entire nose. Generally, the 
electrodes are not worn. General causes of fouling are excessive oil, use 
of non-recommended oil, improper use of the choke, or incorrect carbu-
retion adjustments.

54

ADULT SECTION

Maintenance

Fuel Valve/Fuel Lines

Inspect the fuel valve and the fuel lines regularly. Carefully check the 
system's fuel line condition after periods of storage. Normal deteriora-
tion from weather and fuel compounds can occur. Replace any worn or 
damaged components.

Exhaust System

At approximately 50 hours, check the exhaust system for wear or dam-
age. To inspect, allow the engine and exhaust system to cool completely. 
Open the hood and inspect the muffler and pipes for cracks or damage. 
Check for weak or missing retaining springs or damper/support grom-
mets.

CAUTION

Hot exhaust system parts can cause serious burns. Allow adequate time for 
the exhaust system to cool. Never perform this procedure with the engine run-
ning.

55

ADULT SECTION

Maintenance

Carburetor

NOTICE: Making non-recommended adjustments could result in vehicle or 

engine damage as well as denial of warranty claims. We recommend 
that all carburetor adjustments be performed by your POLARIS 
dealer. 

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 or foreign matter in the carburetor. A mix-
ture 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 to the settings indicated 
by the shaded cells of the jetting chart on page 81. Higher altitude oper-
ation may require different adjustment and settings.

TIP: The number stamped in the end of the main jet indicates the jet size that 

was installed at the time of manufacture.

NOTICE: Using non-recommended jets and/or needles can result in shorter 

engine life, lower fuel economy, increased emissions and poor 
performance and drivability. Always use POLARIS-recommended jets 
and needles.

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

56

ADULT SECTION

Maintenance

Brake Lever Travel

Firmly depress the brake lever. 
Measure the clearance between 
the lever and brake block.

If clearance is more than 3/4" 
(19 mm), adjust the brake 
cable as outlined below. 

Brake Cable Adjustment

If proper adjustment cannot be achieved using the following methods, 
check the brake band. If the brake band has excessive wear, see your 
POLARIS dealer for installation of a new band.

1. Slide the two rubber protector covers back to expose the cable 

adjuster.

2. Using an 8mm wrench to hold the barrel nut, loosen the jam nut 

with a 10mm wrench.

3. With your left hand, grasp the cables as close to the adjuster as pos-

sible. Use your right hand to rotate the barrel nut until you have 
reached the proper brake lever adjustment.

WARNING

Improper brake adjustment can result in brake failure, which could result in 
severe injury or death. Perform the adjustment procedures exactly as outlined, 
or see your POLARIS dealer for service.

3/4" (19 mm)

Rubber Covers

Cables

Barrel Nut

Jam Nut