Snowmobile Arctic Cat 2-Stroke (2007 year). Manual - part 59

4-10

AH137

10. Place the E-clip into position on the jet needle.

From the bottom of the jet needle, slide the E-clip

washer up against the E-clip. Place the jet needle

into the piston valve.

„NOTE: Place the E-clip in the proper position as
noted in disassembly.

725-266C

11. On the 570 cc, place the cable retainer into the pis-

ton valve and secure with the Phillips-head screw.

On the 370 cc, place the spring and plate over the

throttle cable and compress the spring. Guide the

cable end down into the cable retainer slot and

slide the cable end to the center of the piston

valve. Release the spring and retainer plate to lock

the cable in position.

AH075

„NOTE: The round part of the cable end must
come through the hole in the plate/piston valve. If
it doesn’t, the cable isn't assembled to the piston
valve correctly.

12. Thread the plunger cap onto the choke cable. Place

the spring over the cable end and compress. Posi-

tion the cable end into the starter plunger and

release the spring.

Installing Carburetor

„NOTE: On twin carburetor models, install the
carburetors using this basic procedure.

1. Place the carburetor into position in the flange and

air-intake silencer boot; then tighten the flange

clamp making sure the carburetor is level. Do not

over-tighten the flange clamp as it will damage the

carburetor flange.

CM049

„NOTE: Slide the carburetor into the air-intake
silencer boot; then slide the carburetor into the
flange.

2. Connect the fuel hose to the carburetor inlet fit-

ting.

3. Place the piston valve into position making sure

the full-length groove in the piston valve is aligned

with the pin in the mixing chamber bore.

CM055A

! CAUTION

When installing the carburetors, make sure the
gasline hoses are properly routed to avoid prema-
ture wear and/or contact with exhaust components.

4

4-11

4. Thread the brass choke-cable housing into the car-

buretor making sure the washer is properly posi-

tioned and tighten securely.

CM048

5. Secure the mixing body top by tightening the

screw and lock washer making sure the mixing

body top plate is properly positioned.

„NOTE: Prior to threading the mixing body top
onto the carburetor, assure the rubber washer is
positioned correctly on the body top.

6. If applicable, connect the safety switch harness to

the main wiring harness.

7. Turn the gas tank shut-off valve to the OPEN posi-

tion.

8. Adjust the carburetors (see Adjusting Carbure-

tor(s) in this sub-section).

Adjusting

Carburetor(s)

ADJUSTING CHOKE CABLE(S)

1. Be sure the ignition switch key is in the OFF posi-

tion 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 counter-

clockwise 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 clock-

wise while checking the choke cable lever for free-

play. Adjust until 3 mm (1/8 in.) free-play between

front bottom edge of lever and housing is attained.

Securely tighten the adjuster jam nut.

0732-848

5. On twin carburetor models, repeat steps 3 and 4 on

each carburetor.

„NOTE: On twin carburetor models if a carbure-
tor choke cable is adjusted too tight, the engine
will only operate on 1 cylinder at idle.

ADJUSTING PISTON VALVE(S)

„NOTE: On some models, the air-intake silencer
is a one-piece unit, and the silencer boot(s) can be
removed to access the intake bore(s). Remove the
boots; then proceed to step 4.

„NOTE: On some models, the air-intake silencer
includes a cover/tool tray assembly and a baffle/
resonator, and the silencer boot cannot be
removed to access the intake bores. Proceed to
step 1.

1. Open the air-intake silencer cover; then remove

the 3 Phillips-head screws securing the cover/tool

tray assembly to the silencer.

2. Tip the cover/tool tray assembly forward and out

of its slots and remove the assembly.

3. Using a large flat-blade screwdriver, remove the

resonator tabs from the air-intake silencer slots

and remove the resonator to access the intake

bores.

„NOTE: The resonator can be removed more eas-
ily by removing the back tabs first.

4. Rotate each idle speed screw counterclockwise

until all spring tension is removed.

5. Loosen the jam nut securing each throttle cable

swivel adapter; then rotate the swivel adapter

clockwise until the piston valve bottoms in the pis-

ton valve bore.

! CAUTION

The air-intake silencer and boots must be in position
whenever the engine is run. If the silencer is
removed and the engine is run, a lean condition will
result. Therefore, DO NOT run the engine when the
air-intake silencer is removed.

4-12

6. 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.

7. In turn on each carburetor, place a finger against

either piston valve. Rotate the idle speed screw

clockwise until it contacts the valve.

8. Compress the throttle lever to the full-open posi-

tion; then rotate each idle speed screw clockwise 2

complete turns. Release the throttle lever.

„NOTE: On single carburetor models, the throttle
control is equipped with a 2-wire throttle control
switch connector. There must be free-play between
the lever and the control housing.

„NOTE: On twin carburetor models, 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.

0741-518

„NOTE: If cable free-play gap is not correct,
rotate each swivel adapter an equal amount until
recommended free-play is achieved. Each piston
valve must be resting against the tip of its idle
speed screw.

„NOTE: On twin carburetor models if throttle
cable free-play is incorrect, the carburetor safety
switches will be activated prematurely and the
engine will not start.

9. On some models, install the air-intake silencer

boot(s); on some models, install the baffle/resona-

tor and the cover/tool tray assembly.

SYNCHRONIZING PISTON VALVES

„NOTE: Arctic Cat recommends using the Carbu-
retor Synchronizer (p/n 0644-069). If the carburetor
synchronizer is not available, use the following
procedure.

1. Open the air-intake silencer cover; then remove

the 3 Phillips-head screws securing the cover/tool

tray assembly to the silencer.

2. Tip the cover/tool tray assembly forward and out

of its slots and remove the assembly.

3. Using a large flat-blade screwdriver, remove the

resonator tabs from the air-intake silencer slots

and remove the resonator to access the intake

bores.

„NOTE: The resonator can be removed more eas-
ily by removing the back tabs first.

4. Check to make sure the piston valves start to open

at the exact same moment by placing a thumb and

finger against the valves; then lightly compress the

throttle lever.

5. 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 determina-

tion of piston valve opening.

6. If a piston valve starts to open before another,

rotate the swivel adapter on the valve which is lift-

ing first clockwise, just enough to synchronize the

valves. 

„NOTE: Recheck by repeating steps 4-6.

7. Tighten the swivel adapter jam nuts securely. Slide

the rubber throttle cable caps down over the swivel

adapters.

„NOTE: There must be free-play in the throttle
lever.

8. After synchronization has been attained, install the

resonator and cover/tool tray assembly.

! WARNING

Be sure to tighten the swivel adapter jam nuts
securely. If a swivel adapter jam nut is not tightened,
the adjuster can rotate out of the carburetor cap
causing the piston valve not to return to the full-
closed position.

4

4-13

ADJUSTING PILOT AIR SCREW(S)

1. While counting the rotations, carefully rotate each

pilot air screw clockwise until lightly seated.

AH006

2. Rotate each pilot air screw counterclockwise the

same number of turns as noted in step 1 for an ini-

tial setting.

3. Synchronize the oil-injection pump (see Related

Items in this section).

ADJUSTING ENGINE IDLE SPEED

1. With the snowmobile on a shielded safety stand,

start the engine, release the brake lever lock, and

thoroughly warm up. Fine-tune each idle speed

screw and each pilot air screw until the engine

idles smoothly at the desired RPM (1500 RPM is

recommended).

„NOTE: Make engine idle adjustment only after
the engine has reached running temperature.
Since the idle speed screw(s) have not been
adjusted, apply slight throttle pressure to keep the
engine running. Allow engine to warm up for 2-3
minutes.

2. On twin carburetor models after the engine has

been allowed to warm up for 2-3 minutes, adjust

engine idle by first rotating the PTO-side carbure-

tor idle speed screw clockwise until the tachome-

ter reads 1480 RPM.

3. On twin carburetor models, rotate the MAG-side

carburetor idle speed screw clockwise until

tachometer reads 1500 RPM.

AH055

4. On twin carburetor models, rotate the PTO-side

carburetor idle speed screw clockwise until the

tachometer reads slightly above 1500 RPM; then

rotate the idle speed screw counterclockwise to

achieve exact 1500 RPM reading. The piston

valves should now be synchronized and the engine

should idle without holding any throttle pressure.

„NOTE: If the engine has no ignition spark with
the throttle in the idle position but has proper
spark with the throttle lever slightly compressed,
the carburetor safety switches must be reposi-
tioned.

5. Test the throttle control lever by compressing and

releasing it several times. The lever must return to

the idle position quickly and completely.

! CAUTION

Do not force a pilot air screw when rotating it clock-
wise; damage to the pilot air screw needle tip will
result.

! WARNING

DO NOT operate the snowmobile when any compo-
nent in the throttle system is damaged, frayed,
kinked, worn, or improperly adjusted. If the snowmo-
bile is operated when the throttle system is not func-
tioning properly, personal injury could result.