Snowmobile Arctic Cat (2004 year). Manual - part 62

5-15

Troubleshooting

Ignition System

(L/C 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

(L/C 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.

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).

! 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.

5-16

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.

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.

5-17

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,

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.

Throttle Position Sensor

(500/600/700/800/900 cc Models)

NOTE: Ignition timing and fail-safe timing speci-

fications are located at the beginning of this sec-
tion.

DIGITAL 3-D IGNITION (Carbureted
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 CDI 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 500 cc
w/APV is 30° ± 2° BTDC at 2000 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 30° ± 2° at 2000 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.

5-18

NOTE: Procedure for testing the TPS is the same

on carbureted models and EFI models.

CHECKING TPS (Carbureted
Models)

NOTE: On “Laydown” engine models to check

the TPS, Test Harness (p/n 0686-959) must be
used.

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.

4. Using TPS Adjustment Tool (p/n 0644-299),

connect its wiring harness to the TPS. Connect the
two digital voltmeter leads (red and black) using
the two pin jack adapters provided with the
adjustment tool to the white and black jacks of the
TPS adjustment tool.

5. With the throttle in the closed position (valve

resting on the pin gauge), compare the reading on
the voltmeter to the chart. If the reading is at the
prescribed specification, proceed to step 6. If the
reading is not at the prescribed specification,
proceed to Adjusting TPS (Carbureted Models) in
this sub-section.

6. Hold the throttle in the wide-open position; then

compare the reading on the voltmeter to the chart.
If the reading is not within the specification range,
recheck the closed position reading. If the closed
position reading is correct and the wide-open
position reading is not, the TPS is faulty and must
be replaced.

7. If both voltmeter readings are correct, remove the

test harness and pin gauge, install the carburetor
assembly (see Section 4), and connect the
snowmobile TPS harness to the TPS.

NOTE: Before installing the TPS harness con-

nector, apply dielectric grease to the connector
pins.

ADJUSTING TPS (Carbureted
Models)

1. Using TPS Screwdriver (p/n 0644-344), loosen the

two retaining screws securing the TPS to the
carburetor.

2. Adjust the TPS to obtain the correct closed

position reading on the voltmeter.

3. Tighten the two retaining screws securely.

4. To verify TPS position is correct, proceed to steps

6 and 7 of Checking TPS (Carbureted Models) in
this sub-section.

CHECKING/ADJUSTING TPS
(EFI Models)

NOTE: On “Laydown” engine models to check

the TPS, Test Harness (p/n 0686-959) must be
used.

NOTE: Before using the TPS adjustment tool,

verify its battery condition. The battery used in the
tool is a 9-volt battery; also, the Test Harness (p/n
0686-627) must be plugged into the analyzer for
testing voltage.

Engine

Idle

Position

Wide-Open

Position

500 cc

1.7V

3.8V+

600/700 cc
(“Laydown”)

0.50-0.53V

3.9V+

900 cc

0.56V

3.941-4.370V

Content .. 60 61 62 63 ..