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Snowmobile Arctic Cat (2002 year). Manual - part 75

5-19

8. Observe the tachometer and the drive clutch to

determine the moment the carburetor safety

switches shut down the ignition. Since retaining

the throttle lever pin prevents the switch in the

throttle control housing from closing, the

carburetor safety switches should shut down the

ignition at or slightly after clutch engagement.

9. Repeat steps 6-8 several times. If ignition

shutdown always occurs at or slightly after clutch

engagement, the carburetor safety switches are

synchronized.

10. Again, inspect the gap between the throttle lever

and the control housing at idle. Adjust the throttle

cable swivel adapter at the top of each carburetor

for 0.75-1.5 mm (0.030-0.060 in.) cable free-play

gap between the throttle lever “nibs” and the

control housing. While observing if there is any

cable free-play gap, apply slight pressure to the

throttle lever to take up any cable slack that may

be present. However, do not apply enough

pressure to actually raise the carburetor slides

during this adjustment. After cable free-play is

properly adjusted, tighten the jam nut on each

carburetor securely.

NOTE: After completion of any adjustments,

throttle lever “side pressure” should not cause an
ignition miss at idle. Carburetor safety switches
set too low or an excessively tight throttle cable
makes the shutdown system very sensitive to
throttle lever “side pressure” near idle.

Troubleshooting

Ignition System

(Twin L/C & Triple Models)

When troubleshooting the standard “normally open”

ignition system, use the following procedure.

1. Remove the spark plugs and visually check their

condition. Replace any fouled plug. Attach the

spark plugs to the high tension leads and ground

them on the cylinder heads.

NOTE: Make sure the ignition switch and the

emergency stop switch are in the ON position.

2. Crank the engine over and check for spark. If no

spark is present, check to make sure the carburetor

throttle cables are properly tensioned. Compress

the throttle control and while holding the throttle

control in this position, crank the engine over and

check for spark. If spark is now present, adjust the

carburetor throttle cable tension.

3. If no spark is present, disconnect the main wiring

harness from the engine. Crank the engine over. If

spark is present, the problem is either one or more

of the following:
A. Defective emergency stop switch

B. Defective safety switch in throttle-control

handle

C. Corroded or loose wire connection at the

throttle-control housing or main wiring harness

D. Defective ignition switch

NOTE: To check these possible causes, proceed

to Testing Ignition System. If no spark is present,
proceed to Peak Voltage Tests.

Testing Ignition System

(Twin L/C & Triple Models)

NOTE: There must be 0.75-1.5 mm (0.030-0.060

in.) throttle cable free-play between the throttle
lever and the control housing.

MAIN WIRING AND SAFETY

SWITCHES

1. Check the wiring connections coming from the

ignition key, emergency stop, and carburetor

switches (on VM-style). The throttle control

switch connector is located on the front side of the

steering post. If any of the connections appear

dirty or corroded, clean them with fine sandpaper

and compressed air; then connect all wires and

squeeze the connections with a pliers for

additional tightness.

2. Disconnect the main wiring harness connector

coming from the engine stator assembly.

Disconnecting this connector will bypass the main

wiring harness and all switches which will not

allow the engine to be shut off without first

installing an additional auxiliary ground wire.

3. Insert an auxiliary ground wire into the black wire

of the main harness connector on the engine side.

To stop the engine once it has been started, touch

the auxiliary ground wire to the engine.

4. Support the rear of the snowmobile up on a

shielded safety stand; then set the brake lever lock.

Inspect the complete throttle mechanism to assure

that it's working properly.

! CAUTION

Before checking for spark, place all the engine
switches in the deactivated position. In the event
the engine could be flooded, pull the starter rope
(slowly at first) several times to clear the engine
of excess fuel.

! CAUTION

Never crank the engine over without grounding
the spark plugs. Damage to coils and/or CDI unit
may result.

5-20

5. Attempt to start the engine. To stop the engine (if

the engine starts), touch the auxiliary ground wire

installed into the connector to a ground on the

engine. If the engine fails to start, the problem is

with the coils mounted on the engine, high tension

coil assembly, or the CDI unit. If the engine starts,

the problem is with the switches, main wiring

harness, or throttle cable free-play.

MAIN HARNESS

1. Disconnect the main wiring harness connector

coming from the engine stator assembly. Connect

one ohmmeter lead to the violet wire and the other

lead to the brown wire on the chassis side of the

main wiring harness four-wire connector. With all

switches in the RUN position, the meter must read

no resistance (open).

2. If the meter reads resistance (closed), test the

Ignition Key Switch, Throttle Control Switch, and

Carburetor Safety Switches independently of each

other.

IGNITION KEY SWITCH

1. Disconnect the ignition key switch connectors;

then connect the ohmmeter leads to each of the

ignition key switch terminals.

2. With the switch in the OFF position, the meter

must read less than 1 ohm resistance.

3. With the switch in the ON position, the meter must

read OL (infinite resistance).

THROTTLE CONTROL SWITCH

1. Verify that the throttle cable has 0.75-1.5 mm

(0.030-0.060 in.) free-play between the throttle

lever and control housing.

2. Disconnect the throttle control switch connector;

then connect one ohmmeter lead to the brown wire

and the other lead to the black/white wire of the

emergency stop switch.

3. With the throttle lever in the idle position and the

emergency stop knob in the up (RUN) position,

the meter must read no resistance (open). If the

meter reads resistance (closed), replace the switch.

4. With the throttle lever in the idle position and the

emergency stop knob in the down (STOP)

position, the meter must read resistance (closed).

If the meter reads no resistance (open), replace the

switch. With the emergency stop knob still in the

down (STOP) position, move the throttle lever to

the wide open position. The meter must read no

resistance (open). If the meter reads resistance

(closed), replace the switch.

5. Connect one ohmmeter lead to the brown wire and

the other lead to the violet wire. With the

emergency stop knob in the down (STOP)

position, the meter must read resistance (closed).

If the meter reads no resistance (open), replace the

switch. With the emergency stop knob in the up

(RUN) position, the meter must read no resistance

(open). If the meter reads resistance (closed),

replace the switch.

CARBURETOR SAFETY SWITCHES

(VM-Style)

1. Disconnect both carburetor safety switches at the

carburetors from the main wiring harness.

2. Connect the ohmmeter leads to one of the

carburetor safety switches. With the throttle lever

in the idle position, the ohmmeter must read no

resistance (open). If the meter reads resistance

(closed), adjust the switch (see Synchronizing

Carburetor Safety Switches in this sub-section).

Test the remaining switch.

SYNCHRONIZING CARBURETOR

SAFETY SWITCHES

(VM-Style)

Before synchronizing the carburetor safety switches,

check to make certain the carburetor idle speed screws

are adjusted equally and the throttle valves are syn-

chronized. The carburetor safety switches affect igni-

tion spark at idle only. If ignition spark problems are

observed at partial or full-throttle positions, the prob-

lem is not with the carburetor safety switches.

NOTE: There must be 0.75-1.5 mm (0.030-0.060

in.) free-play between the throttle lever and the
control housing.

1. Inspect the cable free-play gap between the

throttle lever and the control housing at idle.

Adjust the throttle cable swivel adapter at the top

of each carburetor for 0.75-1.5 mm (0.030-0.060

in.) cable free-play gap between the throttle lever

“nibs” and the control housing. While observing if

there is any cable free-play gap, apply slight

pressure to the throttle lever to take up any cable

slack that may be present. However, do not apply

enough pressure to actually raise the carburetor

slides during this adjustment. After cable free-play

is properly adjusted, tighten the jam nut on each

carburetor securely.

5-21

733-081C

2. To determine which switch needs adjusting,

disconnect both carburetor safety switches from

the main wiring harness connector.

3. Connect a digital ohmmeter to one carburetor

safety switch connector; then compress the throttle

lever while observing the meter reading and

measure the gap between the throttle lever and

control housing at the moment the meter reading

changes from open to closed. Repeat this step for

the other carburetor safety switch.

NOTE: The correct throttle lever/housing gap

should be in a range of 9.5 - 12.7 mm (0.375-0.500
in.) the moment the meter reading changes from
open to closed. A switch that changes from open
to closed before the other one is the switch that
must be raised to attain safety switch synchroniza-
tion.

733-082A

4. If an adjustment is necessary, loosen the switch

bracket screws, move the switch up, tighten the

screws, and then reset using step 3.

NOTE: After completion of any adjustments,

throttle lever “side pressure” should not cause an
ignition miss at idle. Carburetor switches set too
low or an excessively tight throttle cable makes
the shutdown system very sensitive to throttle
lever “side pressure” near idle. To test carburetor
safety switch synchronization, follow steps 5-9.

5. Reconnect the carburetor safety switch

connectors. Place the rear of the snowmobile on a

shielded safety stand; then start the engine and

allow it to warm up for 3-4 minutes.

6. Hold both the top and bottom of the throttle lever

pin so that depression of the throttle lever does not

move the lever pin in its control slot.

0728-916

7. Slowly depress the throttle lever to increase engine

RPM.

NOTE: It is very important that engine RPM be

allowed to increase slowly, since most engines
have a “rich area” at approximately 2500 RPM.

8. Observe the tachometer and the drive clutch to

determine the moment the carburetor safety

switches shut down the ignition. Since retaining

the throttle lever pin prevents the switch in the

throttle control housing from closing, the

carburetor safety switches should shut down the

ignition at or slightly after clutch engagement.

9. Repeat steps 6-8 several times. If ignition

shutdown always occurs at or slightly after clutch

engagement, the carburetor safety switches are

synchronized.

10. Again, inspect the gap between the throttle lever

and the control housing at idle. Adjust the throttle

cable swivel adapter at the top of each carburetor

for 0.75-1.5 mm (0.030-0.060 in.) cable free-play

gap between the throttle lever “nibs” and the

control housing. While observing if there is any

cable free-play gap, apply slight pressure to the

throttle lever to take up any cable slack that may

be present. However, do not apply enough

pressure to actually raise the carburetor slides

during this adjustment. After cable free-play is

properly adjusted, tighten the jam nut on each

carburetor securely.

NOTE: After completion of any adjustments,

5-22

Digital 3-D Ignition

(500/600/800/

1000 cc Models)

The advantage of a 3-D ignition system is it actually

has up to twelve slightly different timing curves which

are controlled by both throttle position and engine

RPM. This system allows the ECU to select the timing

curve best suited to the operating conditions providing

both maximum performance and increased engine

durability.

When checking the ignition timing, a couple points

must be remembered. First, since the ignition timing is

affected by the throttle position, the throttle position

sensor (TPS) must be in good operating condition and

adjusted correctly. Second, the ignition timing must be

checked according to the following chart. Never

remove the drive belt to make the timing check.

Always place the rear of the snowmobile on a shielded

safety stand and allow the track to rotate freely.

When checking ignition timing, it is important that the

timing light be connected to the number 1 spark plug

wire, which is the MAG-side cylinder. If the number 2

cylinder spark plug wire is used, the timing light may

show a 2° error in ignition timing when ignition timing

is actually correct.

For example, the correct ignition timing on the 1000 cc

is 16° ± 2° BTDC at 3250 RPM.

To quickly check TPS operation, measure the timing

according to the chart; then disconnect the TPS wiring

and recheck the timing. A system with a functioning

TPS will show a change of approximately 4°. This is

known as “Fail-Safe Ignition Timing” and is built into

the system to protect the engine should the TPS fail. If

this change is not seen, the TPS may have failed and

must be checked.

If the ignition timing isn’t 16° ± 2° at 3250 RPM, the

TPS should be checked for proper adjustment using

the TPS Adjustment Tool (p/n 0644-299) and a digital

voltmeter.

TESTING TPS (All Models)

For procedures for testing the TPS, see Testing Indi-

vidual Components in the Batteryless EFI sub-section

of Section 4.

NOTE: Procedure for testing the TPS is the same

on carbureted models and EFI models.

CHECKING TPS (Carbureted

Models)

1. Remove the carburetor assembly from the engine

compartment (see Section 4).

2. Loosen the idle adjustment screw until it is not in

contact with the throttle lever.

AO171

3. Depress the throttle lever to raise the throttle

valves (slides); then insert Pin Gauge (p/n 0644-

345) into the TPS-side carburetor throat beneath

the valve. Slowly release the throttle lever

allowing the valve to rest on the gauge.

AO170

NOTE: The pin gauge MUST be installed on the

engine side of the carburetor.

NOTE: Before using the TPS adjustment tool,

verify its battery condition. The battery used in the
tool is a 9-volt battery. To check battery condition,
use a digital volt/ohmmeter set on DC volt scale.
Test between the adjustment tool black and red
jacks. Insert the red lead of the digital voltmeter
into the red jack of the adjustment tool and the
black lead of the digital voltmeter into the black
jack of the adjustment tool. If voltage is found
below 4.9 volts, replace the battery.

Engine

RPM

Ignition

Timing

± 2°

Fail-Safe

Timing

± 2°

500 cc

2000

25°

12°

600 cc
(Carb - Twin)

2000

24°

12°

600 cc (EFI)

3500

24°

16°

600 cc (Triple)

2000

18°

12°

800 cc (Carb)

2000

14°

12°

800 cc (EFI)

2500

26°

12°

1000 cc

3250

16°

14°

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