Snowmobile Arctic Cat 2-Stroke (2007 year). Manual - part 61

4-18

Major Tuning Components

To assist you in selecting four major tuning components of the carburetor, listed below are the jet needles, needle

jets, pilot jets, and piston valves on charts according to their size.

NOTE: The above needle jets may come in dif-
ferent types; for example, (159) - (166) - (480) -
(224). When selecting a new needle jet, use the
correct series or type.

NOTE: The above chart shows the average per-
formance of a given needle between 1/4 and 3/4
throttle. Needles are constructed in such a way
that at any given point, the needle could be richer
or leaner than the rating it has.

NEEDLE JETS

TYPE - 159-166-480

VM30-32-34-38

TYPE 224

VM40-44

LEAN

N-4

N-6

N-8

O-0

O-2

O-4

O-5

O-6

O-7

O-8

P-0

P-2

P-4

P-5

P-6

P-8

Q-0

Z-0

Q-2

Z-5

Q-3

Z-6

Q-4

Z-8

Q-5

AA-0

Q-6

AA-1

Q-8

AA-2

R-0

AA-3

R-2

AA-5

R-4

AA-8

R-5

BB-0

R-6

BB-5

RICH

R-8

JET NEEDLES

LEAN

6DH2

7F7

6DH3

7DH2

6DH4

7F6

6DH7

7DH3

6DH8

7DH5

6DH41

7H2

RICH

6EGJ1

7J2

PILOT JETS

LEAN

12.5

17.5

22.5

27.5

32.5

37.5

RICH

PISTON VALVES

LEAN

4.0

3.5

3.0

2.5

2.0

1.5

RICH

1.0

4-19

Troubleshooting Fuel

System

Problem: Carburetor Too Rich (0-1/4 Opening)

Condition

Remedy

1. Choke plunger will not seat

1. Adjust — service — replace choke cable — plunger

assembly

2. Pilot air screw too far in

2. Adjust pilot air screw

3. Pilot air passage obstructed — damaged

3. Remove obstruction — replace pilot air screw — carbu-

retor

4. Float/inlet needle obstructed — damaged — adjusted

incorrectly

4. Remove obstruction — replace inlet needle — float —

adjust float tab

5. Pilot jet loose

5. Tighten pilot jet

Problem: Carburetor Too Rich (1/4-3/4 Opening)

Condition

Remedy

1. Pilot air screw too far in

1. Adjust pilot air screw

2. Needle jet — jet needle worn — adjusted incorrectly

— incorrect

2. Replace needle jet — replace — adjust jet needle E-

clip

3. Pilot air passage obstructed — damaged

3. Remove obstruction — replace pilot air screw —

carburetor

4. Pilot jet loose

4. Tighten pilot jet

5. Float/inlet needle obstructed — damaged — adjusted

incorrectly

5. Remove obstruction — replace inlet needle — float —

adjust float tab

6. Main jet loose — too large

6. Tighten — replace main jet

7. Primary air passage obstructed

7. Remove obstruction

Problem: Carburetor Too Rich (3/4-WOT Opening)

Condition

Remedy

1. Main jet loose — too large

1. Tighten — replace with smaller main jet

2. Float/inlet needle obstructed — damaged — adjusted

incorrectly

2. Remove obstruction — replace inlet needle — float —

adjust float tab

3. Needle jet — jet needle worn — adjusted incorrectly

— incorrect

3. Replace needle jet — replace — adjust jet needle E-

clip

Problem: Carburetor Too Lean (0-1/4 Opening)

Condition

Remedy

1. Choke plunger remains seated

1. Adjust — service choke cable — plunger assembly

2. Pilot air screw too far out — damaged

2. Adjust — replace pilot air screw

3. Piston valve sticks open — damaged — worn

3. Service — replace piston valve — throttle cable —

spring

4. Pilot jet — outlet obstructed

4. Remove obstruction

5. Float/inlet needle obstructed — damaged — adjusted

incorrectly

5. Remove obstruction — replace inlet needle — float —

adjust float tab

4-20

Problem: Carburetor Too Lean (1/4-3/4 Opening)

Condition

Remedy

1. Pilot air screw too far out — damaged

1. Adjust — replace pilot air screw

2. Needle jet obstructed

2. Remove obstruction

3. Pilot jet — outlet — main jet obstructed

3. Remove obstruction

4. Float/inlet needle obstructed — damaged — adjusted

incorrectly

4. Remove obstruction — replace inlet needle — float —

adjust float tab

5. Jet needle E-clip position incorrect

5. Adjust E-clip

Problem: Carburetor Too Lean (3/4-WOT Opening)

Condition

Remedy

1. Main jet obstructed — too small

1. Remove obstruction — replace with larger main jet

2. Float/inlet needle obstructed — damaged — adjusted

incorrectly

2. Remove obstruction — replace inlet needle — float —

adjust float tab

3. Needle jet — jet needle obstructed

3. Remove obstruction

Problem: General Fuel System (Engine Cuts Out at High RPM)

Condition

Remedy

1. Fuel delivery inadequate

1. Repair — replace fuel pump — impulse hose

2. In-line fuel filter obstructed — damaged

2. Remove obstruction — replace in-line fuel filter

3. Gasoline contaminated

3. Replace gasoline — de-ice — clean carburetors

4. Gas-tank vent — hose obstructed

4. Remove obstruction — replace vent — hose

Problem: General Fuel System (One Cylinder Runs Lean)

Condition

Remedy

1. Carburetor-to-cylinder air leak

1. Repair — replace gaskets — flanges — service intake

ports — tighten clamps

2. Carburetors not aligned vertically

2. Align carburetors vertically

3. Primary compression (crankcase) low

3. Troubleshoot engine

4. Carburetors not synchronized

4. Synchronize carburetors

4-21

Fuel System

(EFI)

This sub-section has been organized for servicing EFI

fuel systems; however, some components may vary

from model to model. The technician should use dis-

cretion and sound judgment when removing/ disas-

sembling and assembling/installing components.

NOTE: Some illustrations and photographs
used in this section are used for clarity purposes
only and are not designed to depict actual condi-
tions.

Fuel System

(EFI)

Table of Contents

EFI Specifications ................................................. 4-21
Introduction ........................................................... 4-21
Arctic Cat EFI System ........................................... 4-22
Individual EFI Components ................................... 4-23
Self-Diagnostic EFI System (800/1000 cc) ........... 4-26
Self-Diagnostic EFI System (500/600 cc) ............. 4-26
Diagnostic Codes (500/600 cc) ............................. 4-27
ECU (500/600 cc) ................................................. 4-28
Testing Individual Components ............................. 4-28
EFI Analyzer/Diagnostic Tool ................................ 4-31
Peak Voltage Tests and Specifications.................. 4-31
Throttle Body Assembly ........................................ 4-31
Throttle Body Flange............................................. 4-33
Throttle Cable........................................................ 4-33
EFI Component Voltage/Resistance Chart -

Air Temperature ................................................. 4-35

EFI Component Voltage/Resistance Chart -

Water Temperature ............................................ 4-36

Troubleshooting Fuel System................................ 4-37

EFI Specifications

Introduction

The EFI system is lightweight in design and is made

up of a number of components which are explained in

this sub-section. The EFI system eliminates the worry

of changing main jets to compensate for altitude or

temperature. This EFI system will provide quick and

easy starting under all conditions.

The electrical control unit (ECU) has a self-diagnostic

mode built in. It is a very valuable factor in trouble-

shooting. Once the problem area has been determined

from the trouble code flashed by the Check Engine

Light in the speedometer/tachometer, follow the trou-

bleshooting procedure in this sub-section. The chassis

control unit (CCU) codes are flashed by a wrench icon

light incorporated within the speedometer/tachometer.

When troubleshooting the EFI system, special tools

are required. These special tools are the following.

EFI Analyzer Kit (p/n 0744-049)

EFI Analyzer (p/n 0644-476)

Fuel Pressure Test Kit (p/n 0644-493)

Fluke Model 73 Multimeter (p/n 0644-191)

EFI Analyzer Update Kit (p/n 0744-047)

Laptop Diagnostic Tool (p/n 0744-048)

Laptop Diagnostic Test Kit (p/n 0744-050)

NOTE: If using EFI Analyzer (p/n 0644-342) on
the 2007 500/600 cc, Test Harness (p/n 1686-310)
must be used.

Fuel Pressure

42.8-47.3 psi

Coolant Temperature Sensor
(Closes)

194°-206° F (90°-97° C)

Throttle Valve Angle - Volts
(500 cc)

0.714-0.814 - Idle
3.507-4.014 - Full-Open

Throttle Valve Angle - Volts
(600/800 cc)

0.646-0.7540 - Idle
3.472-4.0485 - Full-Open

Throttle Valve Angle - Volts
(1000 cc)

0.595-0.695 - Idle
3.477-4.054 - Full-Open

Content .. 59 60 61 62 ..