Snowmobile Arctic Cat (2008 year). Manual - part 81

5

5-5

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

emergency stop knob in the down (STOP) posi-

tion, the meter must read resistance (closed). If the

meter reads no resistance (open), replace the

switch.

4. Depress the throttle lever with the emergency stop

knob in the up (RUN) position. The meter must

read no resistance (open). If the meter reads resis-

tance (closed), replace the switch.

5. With the throttle lever depressed and the emer-

gency stop knob in the down (STOP) position, the

meter must read resistance (closed). If the meter

reads no resistance (open), replace the switch.

Ignition System

(Twin Carburetor F/C Models)

TESTING

„NOTE: There must be 0.75-1.5 mm (0.030-0.060
in.) free-play between the throttle lever and the
control housing (see Section 4 - Adjusting Carbu-
retors).

Main Wiring and Safety Switches

1. Check the wire connections at the ignition key

switch and at the emergency stop switch. This con-

nector is located on the front side of the steering

post. If any of the connections appear dirty or cor-

roded, clean with fine sandpaper and compressed

air; then connect all wires and squeeze connec-

tions with a pliers for added tightness.

2. Disconnect the main wiring harness connector

coming from the engine. Using an ohmmeter, con-

nect one lead to the black wire in the connector of

the main harness. Connect the remaining ohmme-

ter lead to the brown wire in the connector of the

main harness.

3. With all switches in the RUN position, the meter

must read resistance (closed). If the meter reads no

resistance (open), proceed to testing Emergency

Stop/Throttle Switch, Carburetor Safety Switches,

and Ignition Key Switch.

Emergency Stop/Throttle Switch

1. If the meter read no resistance (open) in the previ-

ous test, locate the wiring harness coming from the

emergency stop/throttle switch assembly.

2. Disconnect the three-wire connector. Using an

ohmmeter, connect one meter lead to the black

wire and the other meter lead to the black/red wire

in the connector.

3. With the emergency stop knob, located on top of

the throttle control, in the ON (pulled up) position

and the throttle lever compressed, the meter must

read resistance (closed).

4. If the meter reads no resistance (open) and the

lever/control housing free-play is correct, replace

the throttle switch.

5. If the meter reads resistance (closed) but the

engine will not start, with the ohmmeter leads still

connected, alternately release and compress the

throttle lever; then move the emergency stop knob

down and up.

6. The meter must read no resistance (open) when the

throttle lever is released and the emergency stop

knob is in either the UP or the DOWN position.

7. If the meter reads resistance (closed), replace the

throttle switch.

8. Connect one meter lead to the black/red wire and

the other meter lead to the black/white wire.

9. With the throttle lever released (idle position) and

the emergency stop knob in the DOWN position,

the meter must read no resistance (open).

10. If above tests were good, proceed to testing Carbu-

retor Safety Switches and Ignition Key Switch.

Carburetor Safety Switches

1. If the meter read no resistance (open) in the previ-

ous test, disconnect the carburetor safety switches

one at time and test for a closed circuit.

2. Attach the two ohmmeter leads to the two leads

coming from each carburetor switch. The meter

must read resistance (closed).

3. If the meter reads no resistance (open), the switch

must either be adjusted or replaced (see Synchro-

nizing Carburetor Safety Switches in this sub-sec-

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

proceed to testing Ignition Key Switch.

Ignition Key Switch

1. If the meter read resistance (closed) in the previ-

ous test, disconnect the ignition key switch con-

nectors and connect the ohmmeter leads to each of

the leads from the switch.

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

must read resistance (closed). If the meter reads no

resistance (open), replace the switch.

5-6

Synchronizing Carburetor Safety 
Switches

Before synchronizing the carburetor safety switches,

check to make certain the carburetor idle speed screws

are adjusted equally and the piston valves are synchro-

nized. The carburetor safety switches affect ignition

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 throt-

tle lever and the control housing at idle. Adjust the

throttle cable swivel adapter at the top of each car-

buretor 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 dur-

ing this adjustment. After cable free-play is prop-

erly adjusted, tighten the jam nut on each

carburetor securely.

0741-518

2. To determine which switch needs adjusting, dis-

connect 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 mea-

sure 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.

0742-349

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 connec-

tors. 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 carbure-

tor safety switches should shut down the ignition

at or slightly after clutch engagement.

5

5-7

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

down 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 con-

trol 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

(EFI Models)

„NOTE: Ignition timing specifications are located
on the Electrical Specifications Chart in Section 1
of this manual.

TESTING TPS

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

is 12° ± 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 in the timing. This is known

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

tem 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 12° ± 2° at 2000 RPM, the

TPS should be checked for proper adjustment using

the Throttle Position Sensor Adjustment Tool Kit and

a digital voltmeter.

VERIFYING TPS ADJUSTMENT 
TOOL 

Before using the TPS adjustment tool, verify its bat-

tery 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 adjust-

ment tool and the black lead of the digital voltmeter

into the black jack of the adjustment tool. The green

power light of the analyzer should now be illuminated.

If voltage is found below 4.9 volts, replace the battery.

„NOTE: The battery used in the tool is a 9-volt bat-
tery; also, the Test Harness must be plugged into
the analyzer for testing voltage.

CHECKING TPS

„NOTE: If the snowmobile is in warranty, breaking
the seal on the idle screw jam nut or the Phillips-
head screws on the TPS will void warranty. If the
TPS is tested out of specification, the throttle
assembly must be replaced. 

„NOTE: Before using the TPS adjustment tool,
verify its battery condition.

1. Using Throttle Position Sensor (TPS) Adjustment

Tool Kit, connect its wiring harness to the TPS.

Connect the red and black digital voltmeter leads

to the white and black jacks of the TPS adjustment

tool.

2. Ensure that the throttle cable/control rod has the

proper amount of free-play.

3. With the throttle in the idle position, compare the

reading on the voltmeter to the chart. If the reading

is within prescribed specification, proceed to step

4.

4. Compress the throttle lever slowly to the full-open

position. The meter reading should show a smooth

rise in voltage all the way to the full-open throttle

position. If the voltage seems to be erratic or

doesn’t meet the prescribed specification, repeat

this procedure several times to confirm results.

5. If the full-open throttle voltage remains erratic or

out of specification; replace the throttle body

assembly.

6. If the TPS is within the prescribed specification,

disconnect the adjustment tool harness from the

TPS. Connect the snowmobile TPS harness to the

TPS.

Engine

Idle Position

Wide-Open Position

500 cc

0.714-0.814

3.507-4.014

600/800 cc

0.646-0.754V

3.472-4.0485V

1000 cc

0.595-0.695V

3.477-4.054V

5-8

„NOTE: Before installing the TPS harness connec-
tor, apply dielectric grease to the connector pins.

FAIL-SAFE IGNITION TIMING

Engines equipped with throttle position sensor have a

protective feature called “fail-safe” ignition timing

which prevents engine damage should the TPS fail. If

the TPS does fail, the engine will run normally at low

RPM but will run poorly at high RPM. This will allow

the operator to get the snowmobile to safety with little

or no engine damage.

„NOTE: The engine will continue to operate this
way until the TPS is replaced.

Testing Electrical 

Resistances

(500/600 cc Models)

„NOTE: Resistance tests of the engine electrical
components should be made using the Fluke Mul-
timeter only. Analog-style multitesters may not be
accurate enough to use in these critical tests.
Replace any component that does not have a test
value within specifications.

IGNITION COIL (Primary)

1. Disconnect the double wire plug from the ECU to

the ignition coil.

2. Set the selector in the OHMS position.

3. Connect the red meter lead to the black/orange

lead; then connect the black meter lead to the

orange/red lead.

FS247A

4. Ignition coil primary resistance must be between

0.24-0.36 ohm.

IGNITION COIL (Secondary)

1. Remove the spark-plug caps from the high tension

wires.

2. Set the selector in the OHMS position.

3. Connect the red meter lead to one high tension

wire; then connect the black meter lead to the

other high tension wire.

AK050D

4. Ignition coil secondary resistance must be between

6800-10,200 ohms.

CHARGE COIL (1)

1. Disconnect the triple-wire plug from the ECU to

the magneto.

2. Set the selector in the OHMS position.

3. Connect the red meter lead to the black/red wire in

the plug; then connect the black meter lead to the

green/red wire in the plug.

AK014

4. Charge coil (1) resistance must be between 7.20-

10.8 ohms. 

CHARGE COIL (2)

1. Disconnect the triple-wire plug from the ECU to

the magneto.

2. Set the selector in the OHMS position.

3. Connect the red meter lead to the brown/white

wire in the plug; then connect the black meter lead

to the green/red wire in the plug.