Snowmobile Arctic Cat (2002 year). Instruction - part 58

 

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Snowmobile Arctic Cat (2002 year). Instruction - part 58

 

 

4-25

4

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/
r es o na tor ,   an d  the   s i le nc e r   boo t  c an not  b e
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

piston valve bore.

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

position; 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
s w i t c h   c o n n e c to r .   Th e r e  m u s t   b e   fr e e -p l a y
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.

733-081C

„

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: 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/

resonator and the cover/tool tray assembly.

SYNCHRONIZING PISTON VALVES

(Sight Glass Method)

„

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. Compress the throttle lever until the dot in each

sight glass on the side of the carburetors is visible.

2. Rotate each swivel adapter until the dots are

equally centered in each sight glass.

AH096A

4-26

0000-084

„

NOTE: It is important that the dots are entirely

within sight glasses, are as equally centered as
possible in the sight glasses, and that one dot is
not significantly higher or lower than another.

3. With the piston valves synchronized, tighten the

swivel adapter jam nuts securely. Slide the rubber

throttle cable caps down over the swivel adapters.

AH125

„

NOTE: There must be free-play in the throttle

lever.

SYNCHRONIZING PISTON VALVES

(Mechanical Method)

„

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

determination of piston valve opening.

6. 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. Recheck by repeating steps 4-6.

AH096A

7. Tighten the swivel adapter jam nuts securely.

Slide the rubber throttle cable caps down over the

swivel adapters.

AH125

! WARNING

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

4-27

4

„

NOTE: There must be free-play in the throttle

lever.

8. After synchronization has been attained, install the

resonator and cover/tool tray assembly.

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

initial 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

carburetor idle speed screw clockwise until the

tachometer 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.

! WARNING

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

! CAUTION

Do not force a pilot air screw when rotating it
clockwise; 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 snow-
mobile is operated when the throttle system is not
functioning properly, personal injury could result.

4-28

Adjusting Carburetors 

(TM-Style)

ADJUSTING CHOKE CABLES (Twin)

1. Be sure ignition switch key is in the OFF position

and the brake lever lock is set.

2. Loosen the jam nut securing each choke cable

adjuster on the side of the carburetor.

0735-774

3. Slowly rotate one choke cable adjuster while

checking the choke lever for free-play. As soon as

all free-play has been removed from the end of the

choke lever, stop rotating the adjuster.

4. With free-play removed from the lever, slowly

rotate the adjuster again while checking the choke

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 jam nut.

0732-848

5. Repeat steps 3 and 4 on the other carburetor.

ADJUSTING CHOKE CABLE (Triple)

1. Be sure ignition switch key is in the OFF position

and the brake lever lock is set.

2. Loosen the jam nuts securing the choke cable to

the bracket at the carburetor.

0735-857

3. Slowly rotate one jam nut while checking the

choke lever for free-play. As soon as all free-play

has been removed from the end of the choke lever,

stop rotating the jam nut.

4. With free-play removed from the lever, slowly

rotate the jam nut again while checking the choke

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 jam nuts.

SYNCHRONIZING THROTTLE VALVES

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. With the throttle in the idle position, select a small

drill bit that will just fit under the cutaway of the

fixed throttle valve.

5. Using the same drill bit, check the clearance under

each adjustable throttle valve cutaway. If

clearance is different from the first carburetor

checked, adjust the throttle valve by loosening the

lever ring locking screw; then using an open-end

wrench, rotate each synchronizing nut in either

direction until the clearance is the same as the first

carburetor checked.

! 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.

 

 

 

 

 

 

 

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