Snowmobile Arctic Cat (2008 year). Manual - part 69

3-20

DISASSEMBLING

1. Secure the recoil starter in a vise.

2. Rotate the roller counterclockwise until the notch

of the roller is near the rope guide in the case.

Guide the rope into the notch and slowly allow the

roller to retract until all recoil spring tension is

released.

FS238A

3. While exerting downward pressure on the friction

plate, remove the bolt/bolt w/washer.

FS239

4. Slowly release the friction plate and lift the plate

with pawl activator free of the recoil roller.

FS240

5. Remove the pawl activator from the friction plate.

FS241

6. Remove the pawl and the return spring; then

remove the friction plate spring.

7. Carefully lift the roller free of the case making

sure the main spring does not accidentally disen-

gage from the case. Account for the bushing.

8. Remove the main spring from the case by lifting

the spring end up and out. Hold the remainder of

the spring with thumbs and alternately release

each thumb to allow the spring to gradually release

from the case.

„NOTE: Do not remove the main spring unless
replacement is necessary. It should be visually
inspected in place to save time.

9. Unwind the rope from the roller, untie the slip-

knot, and remove the rope.

CLEANING AND INSPECTING

„NOTE: Whenever a part is worn excessively,
cracked, or damaged in any way, replacement is
necessary.

1. Clean all recoil starter components.

2. Inspect springs and pawl for wear or damage.

! WARNING

Always wear safety glasses and gloves when servic-
ing the recoil starter.

! WARNING

During the disassembly procedure, continuous
downward pressure must be exerted on the reel so it
does not accidentally disengage and cause injury.

! WARNING

Care must be taken when allowing the recoil roller to
unwind. Make sure all spring tension is released
before continuing.

! WARNING

Care must be taken when lifting the roller free of the
case.

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3

3. Inspect the roller and case for cracks or damage.

4. Inspect the center hub for wear, cracks, or damage.

5. Inspect the rope for breaks or fraying.

6. Inspect the main spring for cracks, crystallization,

or abnormal bends.

7. Inspect the handle for damage, cracks, or deterio-

ration.

ASSEMBLING

739-386A

741-373A

1. Hook the end of the main spring around the

mounting lug in the case.

2. Insert the main spring into the case; then wind it in

a counterclockwise direction until the complete

spring is installed.

„NOTE: The main spring must seat evenly in the
recoil case.

FS242

3. Insert the rope through the hole in the roller and tie

a knot in the end; then wrap the rope counterclock-

wise around the roller leaving approximately 50

cm (20 in.) of rope free of the roller.

4. Apply low-temperature grease to the main spring

and hub.

5. Align the hook in the end of the main spring with

the notch in the roller.

6. Carefully slide the roller over the hub and engage

the spring with the roller; then install the bushing.

FS243

7. Install the return spring making sure the short leg

of the spring is properly installed in the hole in the

roller; then install the pawl making sure the return

spring is properly positioned in the notch of the

pawl.

FS244

8. Slide the end of the rope through the rope guide of

the case; then tie a slip-knot in the rope.

KEY

1. Recoil Starter 

Assy

2. Roller

3. Pawl Activator

4. Friction Plate 

Spring

5. Bushing

6. Pawl

7. Return Spring

8. Friction Plate

9. Bolt

10. Main Spring

11. Cap Screw

570 cc

KEY

1. Recoil 

Starter 
Assy

2. Roller

3. Pawl 

Activator

4. Friction Plate 

Spring

5. Bushing

6. Pawl

7. Return Spring

8. Friction Plate

9. Bolt w/Washer

10. Main Spring

11. Cap Screw

800/1000 cc

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9. Apply a low-temperature grease to the friction

plate. Place the pawl activator into position on the

friction plate making sure the arms of the activator

are properly positioned to the pawl.

FS240

10. Place the friction plate into position allowing it to

rest on the friction plate spring; then install the

bolt/bolt w/washer (coated with blue Loctite #243)

and thread the bolt in until it contacts the friction

plate.

FS245

11. Press down on the friction plate and tighten the

bolt to 11 ft-lb.

FS246

12. With 50 cm (20 in.) of rope exposed, hook the

rope in the notch of the roller.

13. Rotate the roller four or five turns counter-clock-

wise; then release the rope from the notch and

allow the rope to retract.

14. Pull the rope out two or three times to check for

correct tension.

„NOTE: Increasing the rotations in step 13 will
increase spring tension.

INSTALLING

1. Place the starter assembly into position against the

magneto case.

2. Secure the starter with cap screws. Tighten to 8 ft-

lb.

„NOTE: Before tightening the cap screws, slowly
pull the recoil rope until the pawl engages; then
tighten the cap screws. This will center the recoil
against the magneto case.

3. Thread the rope through the bushing in the con-

sole; then install the handle and secure with a knot.

Seat the cap.

4. Release the slip-knot in the rope.

Arctic Power Valve 

(APV) System

The Arctic Power Valve (APV) System adjusts the size

of the exhaust ports to produce maximum horsepower

on the top end while providing excellent low end

power and increased touring fuel economy.

THEORY

Two-cycle engines and their exhaust systems are

designed to produce maximum horsepower in a given

RPM range. This RPM range will change according to

how high (or low) the exhaust port is in relation to the

cylinder. Engines designed for racing have a “high

port” exhaust system and will produce more horse-

power at higher RPM but only with the loss of low end

power and overall fuel economy. “Low port” engines

will produce maximum horsepower in the low RPM

ranges and provide good mid-range fuel economy, but

they sacrifice top end performance. 

The APV system does not increase engine horsepower,

but it does allow the engine to be designed for maxi-

mum top end horsepower without the losses associated

with a “high port” exhaust system.

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3

735-476B

COMPONENTS

The main components of the APV system are the fol-

lowing.

A. Lighting Coil

B. Chassis Control Unit (CCU)

C. ECU

D. Servomotor

E. Power Valve Cables

F. Power Valves

„NOTE: On these models, the traditional regulator/
rectifier has been replaced by a chassis control
unit.

Lighting Coil

The AC current generated by the lighting coil, which

flows to the CCU, is the power source for the APV

system.

Chassis Control Unit (CCU)

The AC current from the lighting coil first enters the

CCU which is then changed from AC current to DC

current. Since the APV circuit cannot use pulsating

DC current, it must be converted (by the CCU) to

straight DC current which is necessary for the APV

system.

ECU

The computer within the ECU has been programmed

to raise and lower the power valves at a specific engine

rpm. When this rpm is reached, DC current is routed to

the servomotor by the ECU.

Servomotor

The servomotor consists of two circuits. One circuit is

a DC circuit, which operates the DC motor within the

servo, and the other is a potentiometer, which mea-

sures the servo pulley position based on voltage.

The computer within the ECU has been programmed

to operate the servomotor between a low and high

voltage range. If voltage is not within the range, the

computer will shut down the APV circuit. The com-

puter will then make a total of three more attempts to

cycle the power valves. If the correct voltage or pulley

position isn’t seen, the APV circuit is shut down and

no more attempts will be made until the engine is shut

down and restarted.

Cables

The exhaust valves are connected to the actuating

cables and, along with the return springs, are contained

inside the APV housing on the exhaust side of each

cylinder. The other end of the actuating cable is con-

nected to the servo.

OPERATION

At idle and low speed operation, the exhaust valves are

held in the “low port” position by the return spring.

When engine RPM reaches a predetermined point, the

ECU will send a signal to the servo which will cycle

and pull the exhaust valves into the up or “high port”

position. The RPM at which the valves open is differ-

ent with each model.

If the servomotor cycles the exhaust valves as

explained above, the exhaust valve circuit is operating

satisfactorily. If the servomotor makes no attempt to

open the valves or if the servo attempts to cycle the

valves three times (then stops working), there is a

problem and it must be corrected.

Servomotor Cycles Three Times

In this situation the ECU computer has been pro-

grammed with a voltage range (low and high) that the

servomotor must operate within. If the servomotor is

put under too much load, its resistance goes up and

may exceed the range upper limit. It will then stop and

attempt two more times. If the resistance still is too

high, it shuts down.

If the servo is commanded to move but the potentiom-

eter output voltage does not change, an error occurs

and the check engine light will flash a trouble code.

Improper servomotor position sensing is normally

caused by one or more of the following:

A. Incorrect exhaust valve cable length (too long

or too short).

B. Exhaust valve cable(s) sticking, broken, or dis-

connected at pulley.

C. Exhaust valves sticking.

D. Exhaust valve spring(s) weak or broken.

Check each of the above probable causes in the order

given to locate the problem of the servomotor cycling

three times in succession; then shutting down.