Snowmobile Arctic Cat 2-Stroke (2007 year). Manual - part 56

3-27

3

FC116

2. Install the new seal using an appropriate-sized seal

driving tool.

FC117

ASSEMBLING/INSTALLING

FC111A

1. Slide the return spring over the end of the actuat-

ing cable.

FC114

„NOTE: Make sure that the small cable end spring
stays in place at the end of the cable.

2. With the cover gasket properly positioned, place

the valve stopper on the cable end and slide it

down until the cable end is inside the stopper.

FC113

3. With the valve plate gasket properly positioned,

slide the exhaust valve through the valve plate and

insert it into the valve stopper. Secure with the

retaining screw. Tighten to 0.6 kg-m (4 ft-lb).

FC112

„NOTE: Note that the exhaust valve gaskets are
directional and must be installed correctly.

4. Slide the valve assembly into the proper cylinder.

KEY

A. Exhaust Valve

B. Cover Gasket

C. Valve Plate

D. Oil Seal

E. Gasket

F. Stopper

G. Stopper Pin

H. Return Spring

I. Valve Cover

3-28

FC115

CM147

FC024

5. Place the valve cover into position on the engine.

Secure with two cap screws (coated with blue Loc-

tite #243). Tighten to 1.4 kg-m (10 ft-lb) on the

600 cc or to 1.1 kg-m (8.0 ft-lb) on the 800/1000

cc.

FC023

6. Perform steps 6-9 in Cable Adjustment in this sub-

section.

TROUBLESHOOTING

The APV system has a self-testing mode built in.

Every time that the engine is started, the servo will

cycle once. The ECU monitors the voltages at the

servo during this cycle to assure they are within opera-

tional tolerances.

If all voltages are within tolerance, the system is ready

for operation. If the voltages are not within tolerance,

the servo will cycle two more times. If the voltages

remain out of tolerance, the system will not operate.

For example, if the headlight and taillight are disabled,

the ECU will sense a high voltage condition and acti-

vate the fail-safe mode. Adding more than 4 amps of

accessories will create a low voltage condition and

activate the fail-safe mode.

The fail-safe mode is an ECU operated engine RPM

limiter. When activated, the fail-safe mode will be

seen as an immediate loss of engine horsepower.

! CAUTION

On the 600 cc, the long side of the exhaust valve
must be facing toward the cylinder head or severe
engine damage may occur.

600 cc

800/1000 cc

Problem: Engine loses power; no top end

Condition

Remedy

1. Exhaust valves stick-

ing in down position

1. Remove carbon depos-

its, burrs, etc.

2. Cables adjusted too

long

2. Inspect—adjust

3.  CCU output voltage out

of tolerance

3. Inspect—replace CCU/

stator

Problem: Poor acceleration; hesitation

Condition

Remedy

1. Exhaust valve sticking

in up position

1. Remove carbon depos-

its, burrs, etc.—inspect/
replace return spring

2. Cables adjusted too

short

2.  Inspect—adjust

3.  CCU output voltage out

of tolerance

3. Inspect—replace CCU/

stator

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3

Exhaust Controlled 

Timing (ECT) System

The APV models are equipped with the Exhaust Con-

trolled Timing (ECT) system which utilizes an exhaust

pipe temperature sensor. This system automatically

adjusts the ignition timing to provide maximum per-

formance through a variety of operating conditions.

The ECU receives input on engine RPM (demand) and

exhaust temperature (engine condition) and adjusts the

ignition timing accordingly. This system is not adjust-

able and is maintenance free. 

If a system fault is suspected, use an ohmmeter to

check continuity of the exhaust pipe temperature sen-

sor located in the expansion chamber. A reading of

either 0 ohm or infinity indicates a failed sensor.

0737-314

„NOTE: A disabled ECT system WILL NOT cause
engine damage; however, a failed ECT system will
have slower throttle response and may produce
slightly less top-end performance.

4

4-1

SECTION 4  —  FUEL SYSTEMS

TABLE OF

CONTENTS

Fuel System (Carbureted) ....................................... 4-2
Fuel System (EFI) ................................................. 4-21
Fuel System (Related Items)................................. 4-37