Snowmobile Arctic Cat (2002 year). Manual - part 51

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3

AP162

3. Remove the retaining pin from the valve stopper.

AP163

4. Slide the valve stopper back on the cable until the

cable end and return spring clear the stopper.

Remove the valve stopper and return spring from

the cable.

AP164

Cleaning and Inspecting

1. Remove all carbon deposits with solvent and a soft

abrasive such as a Scotch-Brite pad.

2. Inspect all parts for nicks, burrs, or other signs of

unusual wear.

Assembling/Installing (600 cc)

AP156A

1. Slide the return spring onto the cable end.

„

NOTE: Make sure the small cable end spring

stays in place at the end of the cable.

2. Place the valve stopper on a clean surface with the

slotted side up; then place the cable in the slot and

pull the cable through the stopper until the cable

end and return spring are in place in the stopper.

Secure with the retaining pin.

AP157

„

NOTE: The retaining pin is inserted long end first

from the right side of the valve stopper. Ensure
that the retaining pin washer is in the recess in the
valve stopper.

3. Assemble the exhaust valve and valve guide as

shown.

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AP165

4. One at a time, slide each of the exhaust valve/

valve guide assemblies through the retaining plate

and onto the pin in the valve stopper.

AP162

„

NOTE: The single center mounting hole on the

retaining plate should be up.

5. Slide the valve assembly into the proper cylinder.

AP154

6. Secure the valve assembly to the cylinder with

three Allen-head cap screws (coated with blue

Loctite #242). Tighten to 1.1 kg-m (8 ft-lb).

AP153

7. Slide the valve cover onto the studs on the engine.

Secure with four nuts. Tighten securely.

AP119

8. Perform steps 6-10 in Cable Adjustment in this

sub-section.

TROUBLESHOOTING

(Carbureted Models)

The APV system has a self-cleaning and self-testing

mode built in. Every time that the engine is started, the

servo will cycle once, and this will wipe-off the carbon

that has accumulated on the exhaust valves. The CDI

unit also monitors the voltages at the servo during this

cycle to assure they are within operational 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.

Problem: Engine loses power; no top end

Condition

Remedy

1. Exhaust valves sticking in 

down position

2. Cables adjusted too long

1. Remove carbon deposits, 

burrs, etc.

2. Inspect—adjust

Problem: Poor acceleration; hesitation

Condition

Remedy

1. Exhaust valve sticking in

up position

2. Cables adjusted too short

1. Remove carbon deposits,

burrs, etc.—inspect/
replace return spring

2. Inspect—adjust

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3

TROUBLESHOOTING (EFI Models)

The APV system used on EFI models is very similar to

that found on carbureted models. The self-cleaning

and self-testing modes are much alike. The main dif-

ference between the two is the higher total electrical

power required by the EFI and APV systems com-

bined. Because of these more demanding power

requirements, the EFI APV system gets power from

the stator lighting coil. The ECU constantly monitors

the power output of the lighting coil, and if the lighting

coil output gets too high or too low, the ECU will acti-

vate the “limp-home” mode. The “limp-home” mode

is an ECU operated engine RPM limiter. When acti-

vated, the “limp-home” mode will be seen as an imme-

diate loss of engine horsepower.

For example, if the headlight and taillight are disabled,

the ECU will sense a high voltage condition and acti-

vate the “limp-home” mode. Adding more than 4 amps

of accessories will create a low voltage condition and

activate the “limp-home” mode.

„

NOTE: When running an APV equipped EFI

engine on a dynamometer, first connect a Voltage
Regulator (p/n 0603-142, 2-wire) or (p/n 0630-643,
3-wire) between the lighting coil and the ECU.
There must also be a minimum 2.5 amp load
installed in-line between the voltage regulator and
the ECU (a 2.5 amp load is equivalent to one high
beam headlight bulb).

Troubleshooting EFI engines with the APV system

should be done with the Arctic Cat EFI Analyzer (p/n

0644-342). To update your existing EFI Analyzer,

order Kit (p/n 0644-341).

Problem: Engine loses power; no top end

Condition

Remedy

1. Exhaust valves sticking in 

down position

2. Cables adjusted too long
3. Lighting coil output 

voltage out of tolerance

1. Remove carbon deposits, 

burrs, etc.

2. Inspect—adjust
3. Inspect—replace stator

Problem: Poor acceleration; hesitation

Condition

Remedy

1. Exhaust valve sticking in 

up position

2. Cables adjusted too short
3. Lighting coil output 

voltage out of tolerance

1. Remove carbon deposits, 

burrs, etc.—inspect/
replace return spring

2. Inspect—adjust
3. Inspect—replace stator

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NOTES