Snowmobile Arctic Cat (2008 year). Manual - part 79

4-32

„NOTE: Before starting the engine, make sure
that no air is present in the testing equipment.

8. With the control arm secured in the FULL-OPEN

position (line-to-line), run the engine at recom-

mended RPM for 2 minutes. Compare the amount

of oil used against the specifications on the chart

in Section 1.

9. If the oil-injection pump output does not meet the

specifications, see Testing Oil-Injection Check

Valves in this sub-section.

10. Disconnect the oil usage tool, remove the plug

from the reservoir, attach the oil-supply hose to the

oil reservoir, and remove the vacuum pump.

„NOTE: After testing the oil pump, it is critical
that the oil pump is correctly synchronized with
the carburetor(s)/throttle bodies (see Synchroniz-
ing Oil-Injection Pump on page 30 in this section).

Testing Oil-Injection

Check Valves

In the event there is an engine problem due to lack of

lubrication, the oil-injection pump check valves should

be tested using a vacuum pump to make sure the check

valves are operating properly.

When testing the check valves, remove them from the

pump assembly.

1. Remove the check valves from the oil-injection

pump.

731-551A

2. Attach the vacuum test pump hose to the check

valve.

3. Squeeze the vacuum pump handle and watch the

pump gauge. The check valve should release at

4.5-5 lb and again reset itself at 3.5-4 lb. If

“release” and “reset” are not within specifications,

replace the check valve.

4. Record the “release” and “reset” readings for the

valve; then perform the test on the other valve.

The “release” and “reset” readings must fall within

specifications and must be within 1.5 lb of each

other. If either or both are not met, replace the

check valves.

5. If the check valves are within specifications but

the oil-injection usage is not, replace the oil-injec-

tion pump.

Fuel Pump

(Carbureted Models)

PRELIMINARY CHECKS

1. Make sure the gas tank shut-off valve is in the

OPEN position.

2. Make sure there is adequate gasoline in the gas

tank.

3. Make sure all hoses are clear and free of kinks and

obstructions.

4. Make sure the fuel filter is not plugged or dam-

aged.

5. Make sure fuel and impulse hoses are in good con-

dition.

6. Make sure there is evidence of good impulse at the

crankcase impulse fitting.

TESTING PRESSURE

1. Connect a pressure gauge between fuel pump and

carburetor using a piece of fuel hose and a T-fit-

ting.

2. Place snowmobile on a safety stand and start the

engine. At the following engine speeds, the speci-

fied pressures must be indicated.

3. Remove gauge and hose and connect fuel hose to

carburetor.

! CAUTION

Whenever servicing the oil-injection system, use a
100:1 gas/oil mixture in the gas tank to ensure ade-
quate engine lubrication. Failure to use the 100:1
mixture to the oil-injection system will result in
severe engine damage.

KEY

1. Gasket

2. Check Valve

3. Gasket

4. Union

! CAUTION

Whenever servicing the oil-injection system, use a
100:1 gas/oil mixture in the gas tank to ensure ade-
quate engine lubrication. Failure to use the 100:1
mixture to the oil-injection system will result in
severe engine damage.

4

4-33

TESTING VACUUM

„NOTE: Make sure adequate fuel is in the carbu-
retor for this test.

1. Turn the gas tank shut-off valve to the CLOSED

position; then disconnect fuel supply hose from

the shut-off valve.

2. Connect a vacuum gauge directly to the fuel pump

inlet fitting.

3. With snowmobile on a safety stand, start the

engine and accelerate to 2000-3000 RPM for a

period of 30 seconds. Note maximum reading of

gauge. Reading must be within the range listed.

4. Stop engine. Connect fuel hose. Turn the shut-off

valve to the OPEN position.

Air-Intake Silencer

(Carbureted Models)

The air-intake silencer is a specially designed compo-

nent used to silence the incoming fresh air and also to

catch the fuel that “spits back” out of the carburetors.

The carburetors are calibrated with the air-intake

silencer in position; therefore, the engine must never

be run with the air-intake silencer removed.

„NOTE: To remove and install the air-intake
silencer, see Section 2.

CLEANING AND INSPECTING

1. Check for holes or cracks in the silencer.

2. Periodically clean the silencer by removing the

cover/tool tray assembly and vacuuming the inte-

rior of the silencer.

Air-Intake Silencer

(Crossfire/M-Series)

The air-intake silencer is a specially designed compo-

nent used to silence the incoming fresh air and also to

catch the fuel that “spits back” out of the throttle body.

The throttle body is calibrated with the air-intake

silencer in position; therefore, the engine must never

be run with the air-intake silencer removed.

REMOVING

1. Remove the two hood pins securing the hood to

the front end; then carefully move the hood back

allowing it to rest against the handlebar.

2. Remove the two screws securing the ECU to the

air silencer. 

3. Using a #20 torx-bit, remove the three screws

securing the air silencer to the front bumper

assembly. Account for the position of the hood

screen.

CLEANING AND INSPECTING

1. Check for holes or cracks in the silencer.

2. Periodically clean the silencer by blowing fresh air

through it.

3. Inspect the air silencer boot and connector for

cracks or wear.

INSTALLING

1. Position the hood screen to the front bumper

assembly; then install the air silencer into the front

end.

2. Secure the air silencer with the three screws.

3. Secure the ECU to the air silencer with the two

screws.

Air-Intake Silencer

(Liquid-Cooled F-Series/

T-Series Models)

„NOTE: A number of servicing procedures for
the liquid-cooled F-Series/T-Series will require that
the air silencer be removed and installed. Pay
close attention to the 

■

NOTE: preceding a particu-

lar servicing procedure that will direct the techni-
cian to this section and sub-section for removing/
installing the air silencer.

REMOVING

1. Remove the hood and the left-side and right-side

access panels; then remove the torx-head screws

securing the console.

741-722A

2. Lift the rear of the console and disconnect the con-

sole/main harness plug-in; then remove the con-

sole.

4-34

3. Remove the springs securing the expansion cham-

ber; then remove the expansion chamber from the

engine compartment. Account for the two exhaust

gaskets.

4. With the seat adjusted to its lowest position,

remove the self-tapping screw from the right-side

seat adjustment track; then remove the seat.

ZJ100A

5. Remove the torx-head screws securing the handle-

bar close-off panel; then remove the panel.

6. Remove the lock nuts and torx-head cap screws

(A) securing the right-side front and rear spar pan-

els; then remove the torx-head screws (D) securing

the left-side rear spar panel to the gas tank and

support tube.

742-207A

„NOTE: The right-side rear spar panel will remain
secured to the chassis.

7. Remove the cap screw located directly above the

ECU securing the air-silencer duct to the front

upper panel; then disconnect the air temperature

sensor and remove the duct.

„NOTE: To aid in accessing the cap screw, the
ECU may be removed.

8. Remove the body screws and flange nuts (C) from

each side securing the front bumper assembly to

the chassis; then remove the two remaining self-

tapping screws (B) from each side securing the

front bumper assembly. Remove the assembly.

„NOTE: At this point, remove the air-intake
silencer and account for the rubber exhaust
bumper.

CLEANING AND INSPECTING

1. Check for holes or cracks in the silencer.

2. Periodically clean the silencer by blowing fresh air

through it.

3. Inspect the silencer dual intake boot and seals for

cracks or wear.

INSTALLING

1. Install the air silencer onto the throttle bodies mak-

ing sure the dual intake boot is properly positioned

and seated.

„NOTE: To aid in installing the air silencer, it can
be helpful to remove the air silencer cover and
work the intake boot over the throttle body from
inside the silencer.

FS201A

2. Place the front bumper assembly (with spar pan-

els) into position on the snowmobile; then secure

the front and rear spar panels together with the

torx-head cap screws and lock nuts (A). Tighten

the lock nuts securely.

742-207A

3. Install the body screws and lock nuts (C) from

each side and the self-tapping screws (B) from

each side securing the front bumper assembly to

the chassis. Tighten all hardware securely.

4

4-35

4. Connect the air temperature sensor and place the

sensor harness beneath the air-intake duct; then

install the duct into the silencer.

„NOTE: To aid in installing the duct, it can be
helpful to apply a thin film of WD-40 to the air
silencer seal and to work the duct back and forth
until the sleeve of the duct is properly seated into
the silencer.

5. Secure the air-intake duct to the upper frame with

the cap screw. Tighten securely.

„NOTE: If the ECU was removed to gain access
to the duct cap screw, install the ECU using the
two cap screws. Tighten the cap screws securely;
then connect the harness plug-ins to the ECU.

FS202A

6. Using the illustration following step 2, secure the

left-side rear spar panel to the gas tank and support

tube with the three torx-head screws (D). Tighten

the screws securely.

7. Install the seat; then install the machine screw

(threads coated with blue Loctite #243) to the right

side of the seat support.

8. Place the rubber exhaust bumper into position on

the air silencer.

FS203A

9. Place gaskets on the resonator and exhaust mani-

fold; then install the expansion chamber. Secure

the chamber to manifold and upper frame with the

springs.

10. Secure the console to the steering support with the

torx-head screws and tighten the screws securely;

then close the left-side and right-side access panels

and close the hood.

741-722A

Gas Tank/Seat 

Assembly

„NOTE: To service the gas tank/seat assembly,
see Section 8.

! CAUTION

Make sure to place the sensor harness beneath the
air-intake duct to avoid contact with exhaust compo-
nents.