Choke Cables; Synchronizing Piston Valves; Piston Valves - Arctic Cat Sno Pro 120 Service Manual

ADJUSTING
CAUTION
The air silencer and boots must be in position when-
ever the engine is run. If the silencer is removed and
the engine is run, a lean condition will result. There-
fore, DO NOT run the engine when the air silencer is
removed.

Choke Cables

1. Be sure the ignition switch key is in the OFF position
and the brake lever lock is set.
2. Loosen the jam nut securing the choke cable
adjuster. Rotate the choke cable adjuster clockwise
until it bottoms against the brass plunger cap.
3. Slowly rotate the choke cable adjuster counterclock-
wise while checking the choke lever for free-play. As
soon as all free-play has been removed from the end
of the lever, stop rotating the adjuster.
4. With free-play removed from the lever, slowly rotate
the choke cable adjuster once again clockwise while
checking the choke cable lever for free-play. Adjust
until 1/8 in. free-play between front bottom edge of
lever and housing is attained. Securely tighten the
adjuster jam nut.
5. Repeat steps 3 and 4 on each carburetor.
 NOTE: If a carburetor choke cable is adjusted too
tight, the engine will only operate on 1 cylinder at idle.

Piston Valves

 NOTE: The air silencer is a one-piece unit, and the
silencer boots can be removed to access the intake
bores. Remove the boots from the carburetor to
access the piston valves.
1. Rotate each idle speed screw counterclockwise until
all spring tension is removed.
2. Loosen the jam nut securing each throttle cable
swivel adapter; then rotate the swivel adapter clock-
wise until the piston valve bottoms in the piston
valve bore.
3. In turn on each carburetor, place a finger lightly
against the side of the piston valve; then rotate the
carburetor swivel adapter counterclockwise until
slight upward movement of the valve is noted.
4. In turn on each carburetor, place a finger against
either piston valve. Rotate the idle speed screw
clockwise until it contacts the valve.
5. Compress the throttle lever to the full-open position;
then rotate each idle speed screw clockwise 2 com-
plete turns. Release the throttle lever.
 NOTE: The throttle control is equipped with a 3-prong
emergency stop switch connector. There must be free-
play between the lever and the control housing.
 NOTE: If cable free-play gap is not correct, rotate
each swivel adapter an equal amount until recom-
mended free-play is achieved. Each piston valve must
be resting against the tip of its idle speed screw.
 NOTE: If throttle cable free-play is incorrect, the car-
buretor safety switches will be activated prematurely
and the engine will not start.
6. Install the air silencer boots making sure they are
properly seated to the carburetor.

Synchronizing Piston Valves

 NOTE: Arctic Cat recommends using a suitable car-
buretor synchronizer. If a carburetor synchronizer is
0732-848
not available, use the following procedure.
1. Move the air silencer boots off the intake bores of the
carburetors.
2. Check to make sure the piston valves start to open at
the exact same moment by placing a thumb and fin-
ger against the valves; then lightly compress the
throttle lever.
3. With slight pressure being applied to the throttle
lever, the piston valves should start to open at the
exact same time. Compress and release the throttle
lever several times to assure accurate determination
of piston valve opening.
4. If a piston valve starts to open before another, rotate
the swivel adapter on the valve which is lifting first
clockwise, just enough to synchronize the valves.
 NOTE: Recheck by repeating steps 2-4.
5. Tighten the swivel adapter jam nuts securely. Slide
the rubber throttle cable caps down over the swivel
adapters.
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