ICS 603GC Shop Manual

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603GC Gas Utility Saw

Shop Manual

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TABLE OF CONTENTS

TITLE603GC SHOP MANUAL

SECTION SECTION TITLE PAGE NUMBER

SHOP MANUAL USE 2

1 TOOLS 3

2 SAW SPECIFICATIONS 4

3 SERIAL NUMBER LOCATION 5

4 SPARE PARTS DIAGRAM (TORQUE AND LOCTITE®) 6

5 AIR INTAKE 19

6 SPARK PLUG 21

7 CLUTCH & RIM SPROCKET 23

8 STARTER SYSTEM 27

9 WALLWALKER 33

CYLINDER COVER 35

11 MUFFLER 39

CARBURETOR 41

CYLINDER & PISTON 43

WATER HOSE 52

IGNITION COIL 53

FLYWHEEL 55

FRONT HANDLE 57

FUEL TANK 58

CRANKCASE 60

20 BAR STUDS 68

TENSIONER 69

22 CARBURETOR TUNING 70

23 IDLE SPEED ADJUSTMENT 74

24 TROUBLESHOOTING DIAGRAMS 75

25 TROUBLESHOOTING: FUEL SYSTEM LEAKS 77

26 TROUBLESHOOTING: CRANKCASE LEAKS 80

APPENDIX

1. SPARK PLUG REFERENCE GUID

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E 81

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SHOP MANUAL USE

TITLE 603GC SHOP MANUAL

Shop Manual Use

This manual contains all the technical information necessary for carrying out repairs on the 603GC cut-off saw. For safe, efficient work, it is of prime importance that the values indicated be adhered to. Routine periodic maintenance is covered in the operator’s manual included with each cut-off saw.

General Shop Rules

• Always use the right tools for the job, otherwise components may be damaged.

• Use a plastic dead blow mallet to separate parts attached solidly to each other.

• Mark mating parts as a reassembly reference.

• Keep component parts together as a group. Assemble screws and nuts into appropriate subgroups.

• When reassembling, clean all parts carefully, lubricate moving parts and replace all oil seals, o-rings, gaskets, washers and self-locking nuts.

• For best results, use only original ICS® replacement parts.

General Recommendations

• Some procedures in this manual require the use of special tools. A complete tool kit for ICS® cut-off saws is available from ICS®.

• Detailed carburetor maintenance and overhaul information is available in Walbro’s Diaphragm Carburetor Service Manual. Walbro can be contacted at http:\\www.walbro.com or by calling 1.989.872.2131.

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603GC SHOP MANUAL

Gas Saw Service Tool Kit - P/N 71572

1. TOOLS

1 2 3 4

6 7 8 9 10

11 12 13

KEY P/N DESCRIPTION

SERVICE 71572 TOOL KIT

1 71521 SCRENCH, 13-19mm

2 71541 PRESSURE GAUGE BULB

3 71542 COIL/FLYWHEEL TIMING SHIM

4 71543 CYLINDER ASSEMBLY CLAMPS & PISTON STOP

5 73462 MAIN BEARING DRIVER TOOL

6 71546 SHOCK ABSORBER TOOL

7 71547 SPARK TESTER

8 71548 FLYWHEEL PULLER TOOL

9 71550 LIMITER CAP REMOVAL TOOL

10 71565

11 71569 INDUCTION SEAL FLANGE W/ SCREWS

12 71570

13 71573

ELECTRONIC TACHOMETER

EXHAUST SEAL FLANGE W/ SCREWS

TUNING SCREWDRIVER

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2. SPECIFICATIONS

SPECIFICATIONS

Engine Type 2-Stroke Single Cylinder Air Cooled

Displacement 3.9 cu. in. (64 cc)

Horsepower 4.2 hp (3.1 kW) @ 9500 rpm

Engine Speed 12,500 ± 500 rpm, electronically governed

2800-3200 rpm @ idle

Weight 18.5 lbs. (8.4 kg) with bar and chain

Cutting Depth Up to 9 inches (23 cm)

Dimensions 18 inches (45 cm) length

11.5 inches (29 cm) height 10 inches (25 cm) width

Carburetor Walbro diaphragm HDA-225

Air Filtration Canister, polyester

603GC SHOP MANUAL

Starter Dust and water shielded

Ignition Electronic speed governing, water sealed

Clutch Three-weight, single spring, centrifugal

Fuel Mix Ratio 25:1 gasoline to oil with brand name gasoline and

ICS® 2-stroke engine oil, or other high quality 2-stroke engine oil for air cooled engines.

Fuel Capacity (0.18 gal / 0.68 lit)

15-18 minute run time

Water Supply Minimum 20 psi (1.5 bar)

Noise Level 100 db @ 1 meter

Vibration Level 11.0 m/s

Spark Plug TYPE Champion RCJ-7Y (for spark plug reference guide see page 81)

Spark Plug Gap 0.02 inches (0.5 mm)

Sprocket Type 8-tooth rim sprocket

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603GC SHOP MANUAL

3 603GC Cut-Off serial number series.

3. SERIAL # LOCATION

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4. SPARE PARTS DIAGRAM

603GC SHOP MANUAL

4 This section covers torque, Loctite®, and lubrication requirements of the individual

components. The key numbers used are not related to the key numbers in the 603GC Replacement Parts Price List.

CYLINDER & PISTON ASSEMBLY

KEY DESCRIPTION

6 WRIST PIN NEEDLE BEARING 505403 11 CYLINDER BLOCK BOLT & WASHER 1.1 95 X 73874 16

CYLINDER BASE GASKET 505439

SPARK PLUG 2.8 243 73199 25 COMPLETE CYLINDER & PISTON ASSEMBLY 505428 33 WASHER 73963 50 SCREW PLUG 73965 60 DECOMPRESSION VALVE 1.3 113 71642

TORQUE LOCTITE

Nm in‑lbs. 242

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603GC SHOP MANUAL

CRANKCASE ASSEMBLY

4. SPARE PARTS DIAGRAM

KEY DESCRIPTION

1 CR ANKCASE PLUG 505407 2 CR ANKCASE 505410 3 CR ANKCASE DOWEL PIN 73281 4 CHOKE LEVER 505409 5 BAR MOUNTING STUD 509555 6 CR ANKCASE GROMMET 505408 7 WASHER 73897 9 BAR MOUNT PAD COVER PLATE 505467

CRANKCASE GASKET 505440

CHOKE LEVER BUSHING 73955

CRANKCASE BOLT 0.8 69 X 73930

SCREW, 5 X 50mm 0.5 43 X 509709 22 CRANKCASE 505427 25 TENSIONER 505393 27 CRANKSHAFT BEARING 505375 28 FUEL LINE GROMMET 505627

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TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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4. SPARE PARTS DIAGRAM

CLUTCH & CRANKCASE ASSEMBLY

603GC SHOP MANUAL

KEY DESCRIPTION

8 CLUTCH SPRING 505434

CRANKCASE SEAL RETAINER 505423 11 CRANKSHAFT SEAL 505381 14

CLUTCH SPACER 505421 16

CLUTCH 3.4 295 505442 17

CLUTCH SPACER INSIDE 505436 20 CLUTCH BEARING 505378 21

8T RIM SPROCKET KIT 70949 23 OUTER CRANKCASE SEAL BODY SCREW 0.3 26 X 73940 24 WAVE WASHER, 4.5mm 73285 26 CLUTCH CUP WITH SPLINED ADAPTOR 505422

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

KEY DESCRIPTION

1 CR ANKSHAFT SEAL FLYWHEEL SIDE 73877 2 CR ANKSHAFT BEARING 505375 4 CR ANKSHAFT SEAL 505381 5 CR ANKSHAFT BUSHING X 509487 6 WRIST PIN NEEDLE BEARING 505403 7 CR ANKSHAFT ASSEMBLY 505397

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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603GC SHOP MANUAL

MUFFLER ASSEMBLY

4. SPARE PARTS DIAGRAM

KEY DESCRIPTION

1 MUFFLER SUPPORT BRACKET SCREW 0.9 78 X 73885 2 SERRATED WASHER 73327 3 MUFFLER SUPPORT BRACKET 505392 4 MUFFLER MOUNTING SCREW 1.0 87 73883 5 SCREW 0.4 35 71482 6 WASHER 73897 7 MUFFLER DEFLECTOR 505396 9 MUFFLER ASSEMBLY 505418

CYLINDER-TO-MUFFLER GASKET 505385

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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4. SPARE PARTS DIAGRAM

CARBURETOR ASSEMBLY

603GC SHOP MANUAL

KEY DESCRIPTION

1 SCREW 0.4 35 X 73866

2 INTAKE MANIFOLD CLAMP 73867

3 INTAKE MANIFOLD 505383

CARBURETOR PULSE TUBE 73898

32 CARBURETOR SPRING 73888

36 WASHER 73897

38 CARBURETOR ATTACHMENT SCREW 0.5 43 X 73902

49 OUTER INTAKE MANIFOLD FLANGE SCREW 0.4 35 X 73901

54 CARBURETOR MOUNTING BRACKET 505411

55 CARBURETOR 505654

63 OUTER INTAKE MANIFOLD FLANGE 505384

OUTER INTAKE MANIFOLD 507427

65 ADJUSTMENT GUIDE 505391

BREATHER TUBE BODY 71751

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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603GC SHOP MANUAL

FUEL TANK & HANDLE ASSEMBLY

4. SPARE PARTS DIAGRAM

KEY DESCRIPTION

1 FUEL TANK 505655 2 REAR HANDLE HALF 505389 3 SCREW 0.1 9 73976 4 THROTTLE LEVER 73977 5 FUEL CAP ASSEMBLY, WITH OUTER SEAL RIING 71739 7 SHOCK ABSORBER WITH SCREW 505658 8 BREATHER TUBE BODY 71751 9 SCREW 0.9 78 X 73982

WASHER 73897 11 FRONT HANDLE BOLT 0.8 69 X 73983 12

FRONT HANDLE 505424 13

FUEL FILTER 73459 14

FUEL LINE 73375 15

FUEL CAP O-RING 73448 16

TRIGGER LOCKOUT LEVER 73987 17

TRIGGER LOCKOUT LEVER SPRING 73988 18

BUMPER, SHOCK ABSORBER, FUEL TANK TOP 73270 25 FUEL BREATHER COMPLETE 71748 27 REAR HANDLE SHOCK ABSORBER 505425 31

TUBE CLAMP, WITH TABS 71588 32 BREATHER TUBE ELBOW 71759 33 TUBE CLAMP, NO TABS 71760 35 FUEL BREATHER, REMOTE 71761 38 RUBBER WATER DEFLECTOR 505445 41

SHOCK ABSORBER 0.4 35 505387

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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4. SPARE PARTS DIAGRAM

TITLE 603GC SHOP MANUAL

FLYWHEEL ASSEMBLY

KEY DESCRIPTION

31 FLYWHEEL SHROUD 505438 45 FLYWHEEL 505399 48 NUT 3.0 260 73891 51

WAVE WASHER 73911 57 PLAIN WASHER 73912 71

STARTER PAWL ASSEMBLY 0.7 61 508852

TORQUE LOCTITE

Nm in‑lbs. 242

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603GC SHOP MANUAL

IGNITION ASSEMBLY

4. SPARE PARTS DIAGRAM

KEY DESCRIPTION

39 WAVE WASHER, 4.5mm 73285 40 SPARK PLUG CAP & SPRING KIT 73241 41

SPARK PLUG SPRING 73917 43 IGNITION TOGGLE CABLE 73919 44 IGNITION COIL 505426 47 SWITCH, IGNITION TOGGLE 73237 53 SCREW 0.7 61 X 73914 56 PLAIN WASHER 0.3 26 73890 59 IGNITION TOGGLE SWITCH NUT 73239 61

IGNITION TOGGLE PLATE ON/OFF 73238 66 SWITCH GROUND CONNECTION PLATE 71449

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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4. SPARE PARTS DIAGRAM

STARTER ASSEMBLY

603GC SHOP MANUAL

KEY DESCRIPTION

1 SCREW 0.4 35 X 73866 26 STARTER ROPE HANDLE 505514 27 STARTER ROPE 508854 30 STARTER PULLEY SCREW 0.6 52 X 73907 34 RECOIL HOUSING SCREW 505380 35 STARTER PULLEY WASHER 73905 37 STARTER ROPE PULLEY 508857 42 STARTER ASSEMBLY 505416 58 STARTER COIL SPRING & HOUSING 73909 62 STARTER CASE PLATE 71451 72 STARTER ASSEMBLY CAP 508853

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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603GC SHOP MANUAL

AIR FILTER ASSEMBLY

4. SPARE PARTS DIAGRAM

KEY DESCRIPTION

1 CYLINDER COVER 505691 2 AIR FILTER CANISTER, POLY 71752 3 AIR FILTER COVER ASSEMBLY, 3 SCREW 0.4 35 71753 4 FILTER COVER SCREW 73992 5 FILTER SUPPORT 73338 6 FILTER COVER GASKET 71756 7 CYLINDER COVER SCREW 0.5 43 X 505429 8 PREFILTER PLASTIC, SECONDARY FILTER 73336 9 AIR FILTER FLANGE 71758

FILTER SUPPORT SCREW 0.3 26 X 505437 11 FILTER CANISTER GASKET 73335 12

O-RING 71472 13

TUBE CLAMP, NO TABS 71760 14

COMPENSATOR TUBE 505382 15

BREATHER GROMMET 71763 16

THROTTLE ASSEMBLY 71750 17

O-RING, AIR FILTER 73331 18

WASHER 73897

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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4. SPARE PARTS DIAGRAM

WATER DELIVERY SYSTEM

603GC SHOP MANUAL

KEY DESCRIPTION

1 HOSE CLAMP 71465 2 WATER HOSE 509488 3 WATER HOSE COVER 71464 4 HOSE HANGER 71461 5 WATER SHUT-OFF VALVE 71458 6 WATER HOSE O-RING 71468 7 RING NUT 71457 8 FITTING 71467

WATER HOSE GASKET 71469 24 FITTING 71454 27 FITTING 71466

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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603GC SHOP MANUAL

SIDE COVER ASSEMBLY

4. SPARE PARTS DIAGRAM

KEY DESCRIPTION

9 SIDE COVER 505415

SIDE COVER NUT 1.2 104 73958 11 GUARD FLAP NUT 505468 12

SCREW 0.5 43 73982 13

GUARD FLAP MOUNTING BRACKET (BACK) 505490 14

GUARD FLAP MOUNTING BRACKET (FRONT) 505491 15

GUARD FLAP SCREW 71479 16

GUARD FLAP 505492 17

RUBBER BUMPER, COVER 73310 18

SCREW 71487 19

SIDE COVER PLATE 505419 20 SIDE COVER GASKET 505417 21

MOUNTING NUT 509852 22 RUBBER WALLWALKER 505493 23 FITTING X 71454 24 BOLT 73983

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TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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4. SPARE PARTS DIAGRAM

CARBURETOR REPAIR KIT

603GC SHOP MANUAL

KEY DESCRIPTION

ABOVE CARBURETOR WALBRO HDA-225 517742

CARBURETOR REPAIR KIT 505441

TORQUE LOCTITE

Nm in‑lbs. 242

PART NUMBER

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5 This section covers the

disassembly, inspection, and assembly air induction system.

5.1 Loosen the air filter cover screws and remove air filter cover.

5.2 Remove air filter from cover.

A I

nspect air filter.

B Replace if necessary (P/N 71752).

TITLE603GC SHOP MANUAL

5. AIR INTAKE

5.3 Remove secondary filter from air filter mount.

A Clean secondary filter with cleaning

solution and a nylon brush.

B Let dry and reinstall.

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TITLE 603GC SHOP MANUAL

5. AIR INTAKE

5.4 Inspect air filter cover gasket.

A Replace if permanently depressed

or hard due to slurry.

5.5 Inspect filter cannister gasket.

A Clean.

B Replace if necessary.

5.6 Secure air filter mount screws (3) using Loctite® 242.

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6 This section covers the removal,

inspection, and installation of the spark plug.

6.1 Remove the spark boot taking care

not to pry or damage the wire.

6.2 Clean area around the spark plug

to prevent debris from entering the cylinder.

6.3 Remove the spark plug.

TITLE603GC SHOP MANUAL

6. SPARK PLUG

6.4 Inspect the spark plug for proper

size, gap and condition.

A If dirty, clean with a wire brush

as shown.

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TITLE 603GC SHOP MANUAL

6. SPARK PLUG

B Gap if necessary to 0.02” (0.5 mm).

NOTE: If the spark plug must be

replaced refer to the Spark Plug Reference Guide on page 81 to select the correct replacement plug.

6.5 Assemble in the reverse order.

A M

ake sure the plug boot is

seated completely.

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7 This section covers clutch

removal, rim sprocket removal, inspection, and assembly. Refer to sections 5 and 6 if needed.

7.1 Insert piston stop tool into

spark plug hole.

7.2 Pull starter handle until piston stops

against tool.

7. CLUTCH & RIM SPROCKET

TITLE603GC SHOP MANUAL

7.3 Remove clutch.

Left hand threads – rotate

clockwise to loosen.

NOTE: If an impact wrench is available

steps 7.1 and 7.2 do not have to be performed.

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7. CLUTCH & RIM SPROCKET

TITLE 603GC SHOP MANUAL

7.4 Remove all drive components.

7.5 Inspect the clutch shoes for wear.

A R

eplace if the shoe has less than

0.04” (1 mm) of material, as shown.

7.6 Inspect spring for cracks.

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7.7 Assemble clutch.

7. CLUTCH & RIM SPROCKET

TITLE603GC SHOP MANUAL

A Insert top edge of clutch shoe

over spring as shown.

B Snap clutch shoe into place.

7.9 Inspect the rim sprocket for wear.

A Replace if the rim sprocket teeth are

worn to points, as shown on right.

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7. CLUTCH & RIM SPROCKET

TITLE 603GC SHOP MANUAL

7.10 Clean and assemble.

A C

B G

lean all parts in solvent.

rease clutch cup bearing with a water proof grease (ICS® P/N 70885).

C A

ssemble clutch spacer washer, bearing, clutch cup with rim sprocket, and inside clutch spacer washer.

7.11 Install clutch.

A T

ighten firmly.

Left hand threads

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8 This section covers the

removal of the starter cover, replacement of the starter rope, and replacement of the recoil spring.

8.1 Remove starter cover screws.

8.2 Remove starter cover assembly

from saw.

8.3 Remove starter cord shield screws.

TITLE603GC SHOP MANUAL

8. STARTER

8.4 Relieve spring tension.

A Pull 4-6” (10-15 cm) of rope out.

B Line rope up with notch on pulley.

C To release pulley, slowly rotate

pulley counterclockwise until spring pressure is released. Use thumb as a brake.

8.5 Remove rubber screw seal.

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TITLE 603GC SHOP MANUAL

8. STARTER

8.6 Remove starter pulley.

A Remove pulley screw.

8.7 Inspect coil spring.

A R

eplace if spring hook is damaged. Attempting to re-bend the spring hook may cause the hook to break off.

B Carefully remove coil spring

and housing to prevent spring from unwinding.

8.8 Lubricate with light weight oil.

8.9 Replace parts carefully.

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8.10 Inspect pulley spring catch.

TITLE603GC SHOP MANUAL

8. STARTER

A C

B R

8.11 Install starter rope and tie knot.

lean with cleaning solution.

eplace if worn or broken.

8.12 Knot tying instructions:

A Make a loop at the end of the

pulley rope with the end of the rope crossing on top of the tail.

B Bring the end of the rope through the

loop, creating a single loose knot.

C Pull the end of the rope down and in

front of the tail.

D Send the end through the loop a

second time, creating a double knot; cinch tight.

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A B

C D

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TITLE 603GC SHOP MANUAL

8. STARTER

8.13 Install pulley.

A W

ind rope onto pulley clockwise

leaving 4-6” out.

B Make sure that the pulley spring

catch is in the spring hook.

8.14 Install center screw.

A Use Loctite® 242.

orque to 26 in-lbs. (2.9 Nm).

B T

8.15 Wind the recoil spring.

A L

ine rope up with notch on pulley.

B R

otate the pulley with the rope clockwise 5 times.

C Untangle rope and release.

8.16 Assemble starter cord shield.

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8.17 Remove starter pawl screws, pawls,

spring, and plain washer.

8.18 Inspect and clean pawl components.

nspect the components.

A I

Replace if necessary.

TITLE603GC SHOP MANUAL

8. STARTER

B C

lean the components with a brush

and solvent.

8.19 Assemble components.

A Make sure the spring is in the

correct position.

B Use Loctite® 242 on the pawl screws.

C Torque to 60 in-lbs. (6.8 Nm).

8.20 Install starter cover.

A Pull out cord 4-6”.

B Slowly release while placing cover

to allow pawls to engage.

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TITLE 603GC SHOP MANUAL

8. STARTER

8.21 Install starter cover screws.

A U

B T

se Loctite® 242.

orque to 60 in-lbs. (7 Nm).

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9 This section covers the removal,

inspection, and assembly of the rubber padded wallwalker and guard flap.

9.1 Inspect bumpers.

A Replace if worn.

9.2 Remove side cover assembly.

9.3 Remove cover plate.

9. WALLWALKER

TITLE603GC SHOP MANUAL

9.4 Remove crankcase screws and

wave washers.

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9. WALLWALKER

TITLE 603GC SHOP MANUAL

9.5 Remove and inspect guard flap.

A R

eplace the flap if it is torn or damaged in any way.

9.6 Remove guard flap screws and washers.

9.7 Reassemble in the reverse order.

A Install crankcase screws and

wave washers.

B Use Loctite® 242.

C Torque to 70 in-lbs. (7.9 Nm).

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10 This section covers the

disassembly and assembly of the cylinder cover. Removal of the air intake components and front handle is necessary. Refer to sections 5 and 17 if needed.

10.1 Remove the air filter mount screws.

NOTE: May require heat to

remove screws.

10.2 Remove the cylinder cover screws (3).

10.3 Remove spark plug boot from cylinder

cover taking care not to pry or damage the wire.

10. CYLINDER COVER

TITLE603GC SHOP MANUAL

10.4 Remove fuel tank breather cap

and clamp.

10.5 Partially remove intake manifold

from cylinder cover.

10.6 Remove cylinder cover.

A Pull up on front.

B Push intake manifold through hole.

C Make sure throttle linkage is

disengaged from cylinder cover.

D Guide fuel breather tube and

compensator tube through cylinder cover.

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10. CYLINDER COVER

TITLE 603GC SHOP MANUAL

10.7 Remove stop switch leads.

10.8 Inspect cylinder cover for damage.

A Replace if necessary.

10.9 Check filter cover gasket.

A R

eplace if necessary.

10.10 Check cylinder cover water seal.

A R

eplace if necessary.

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10.11 Assemble in reverse order.

A Reassemble stop switch leads.

10.12 Make sure carburetor screw boot

is in place.

10. CYLINDER COVER

TITLE603GC SHOP MANUAL

10.13 Install cylinder cover.

A P

B Lubricate compensating tube (1) and

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ull spark plug lead into slot

in cylinder cover.

fuel tank breather tube (2) with soapy water, guide through cylinder cover (Install compensating tube first).

NOTE: Be careful to not pull tubes away

from their point of connection. Approximately 3/4” of tube should protrude from cylinder cover.

B (1)

B (2)

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10. CYLINDER COVER

C Push the cylinder cover down on the

crankcase, guide intake manifold into cylinder cover.

603GC SHOP MANUAL

D Align throttle linkage with cylinder

cover and crankcase.

nstall the cylinder cover screws.

E I

Use Loctite® 242. Torque to 35 in-lbs. (4.0 Nm).

10.14 Install air filter mount.

A G

uide carburetor compensating tube through air filter mount. Make sure manifold sits flat over lip on cylinder cover.

B Install air filter mount screws (3) using

Loctite® 242.

orque to 43 in-lbs. (4.9 Nm).

C T

10.15 Install air filters and cover.

A Install pre-filter.

B Install clean air filter.

C Install air filter flange and tighten.

D Install air filter cover and tighten.

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603GC SHOP MANUAL

11 This section covers the

disassembly, inspection, and assembly of the muffler. Removal of the bumpers and cylinder cover is necessary. Refer to sections 9 and 10 if necessary.

11.1 Remove muffler support screws.

11.2 Remove muffler screws (2) – note

there are two screws – and serrated washers located inside the muffler.

11. MUFFLER

11.3 Remove muffler and heat shield

gasket.

A Replace any damaged components.

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11. MUFFLER

11.4 Install muffler.

A I

nsert muffler screws and serrated

washer (2) into muffler.

B Hold muffler screws in place with

heat shield gasket.

hread muffler screws into cylinder,

C T

torque to 78 in-lbs. (9 Nm).

11.5 Install muffler support.

A Install top 3 muffler support screws

and serrated washer finger tight.

603GC SHOP MANUAL

B Install bottom 2 muffler support

screws with Loctite® 242.

C Torque top screws to

78 in-lbs. (9 Nm).

D Torque bottom screws to

52 in-lbs. (6 Nm).

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603GC SHOP MANUAL

12. CARBURETOR

12 This section covers the

removal and installation of the carburetor. Removal of the air intake components and cylinder cover is required. Please refer to sections 5 and 10 or 11 if necessary. Carburetor tuning is covered in section 22.

12.1 Remove throttle linkage.

A P

B P

C Remove carburetor end of linkage

ush trigger end out of rear handle.

ivot linkage around.

from throttle rod tab on carburetor.

NOTE: All saws are equipped with carburetor model # HDA-225.

12.2 Remove fuel line from carburetor and

support bracker.

12.3 Remove carburetor support bracket.

A Remove carburetor support screw (1)

with #4 Torx or straight blade screwdriver.

B Remove carburetor body screws (2).

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Page 44

12. CARBURETOR

12.4 Remove carburetor.

A Remove pulse tube.

B Remove carburetor jet cover.

C Remove carburetor from

choke linkage.

12.5 Assemble in the reverse order.

A Torque carburetor body screws to

43 in-lbs. (5 Nm).

603GC SHOP MANUAL

orque supporter screw with

B T

Loctite® 242 to 43 in-lbs. (5 Nm).

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Page 45

603GC SHOP MANUAL

13. CYLINDER & PISTON

13 This section covers the

disassembly, inspection and assembly of the cylinder, piston and related components. Removal of several component groups is required. Refer to sections 5, 6, 10, and 12 if necessary.

13.1 Remove carburetor base screws.

A R

B Remove carburetor base bracket

emove carburetor base bracket

from rear manifold.

from pulse tube.

NOTE: When replacing the 603GC cylinder

and piston it is necessary to tune the carburetor prior to returning the saw to service (see section 22).

13.2 Remove pulse tube and protective

spring from cylinder base.

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Page 46

13. CYLINDER & PISTON

13.3 Remove rear manifold clamp.

13.4 Remove rear manifold from cylinder.

A Inspect for holes and tears.

13.5 Remove cylinder screws (4) and wave washers.

603GC SHOP MANUAL

13.6 Remove cylinder.

A R

emove cylinder gasket and

clean case.

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603GC SHOP MANUAL

13.7 Remove wrist pin retaining clips (2).

13.8 Press wrist pin out with an 8 mm

deep socket.

13. CYLINDER & PISTON

13.9 Remove piston and inspect.

Replace if damaged.

13.10 Remove wrist pin bearing.

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13. CYLINDER & PISTON

13.11 Assemble cylinder gasket.

603GC SHOP MANUAL

A O

il gasket with ICS® 2-stroke

engine oil.

B Install and align holes and notch.

13.12 Install wrist pin bearing in rod.

A O

il bearing with ICS® 2-stroke

engine oil.

13.13 Install rings.

A Install lower ring first for ease

of installation.

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603GC SHOP MANUAL

13.14 Ring orientation.

13. CYLINDER & PISTON

NOTE:

Make sure both piston ring end gaps are correctly oriented over their locating pins in the piston ring grooves.

13.15 Install one wrist pin retaining clip.

13.16 Make sure wrist pin retaining clip is in

the proper orientation.

Improper installation may result

in serious engine damage.

NOTE: Never attempt to reuse wrist pin

retaining clips or substitute wrist pins from another model or brand. Install two new retaining clips with their open ends facing either to the six o'clock (toward the crankcase) or twelve o'clock (toward the cylinder head) position. Each retaining clip should produce an audible "click" as it seats in its groove in the piston.

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13. CYLINDER & PISTON

13.17 Lube and partially install wrist pin.

13.18 Align piston in correct orientation.

603GC SHOP MANUAL

A Make sure arrow points to

exhaust port.

13.19 Install piston.

A O

il piston with ICS® 2-stroke oil.

B Align wrist pin with wrist pin bearing.

C Complete wrist pin installation.

D Install second wrist pin retaining clip.

EXHAUST

INTAKE

Make sure wrist pin retaining

clip is in the proper orientation (see 13.16).

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603GC SHOP MANUAL

13.20 Install cylinder.

A L

ubricate cylinder bore with

ICS® 2-stroke oil.

B Compress rings with ring

compression tool.

13. CYLINDER & PISTON

C S

lide cylinder onto piston, pushing

ring compression tool down.

13.21 Install cylinder.

A Remove ring compression tool.

B S

lide cylinder down piston and

into crankcase.

C Align cylinder bolt holes with

crankcase.

13.22 Install 4 cylinder screws and

washers.

A Use Loctite® 242.

B Torque bolts to 95.5 in-lbs. (11 Nm).

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13. CYLINDER & PISTON

13.23 Install rear manifold.

Apply lightweight grease on the inside lip of the rear manifold.

B Push rear manifold onto

cylinder intake.

Align mold seams of intake boot with

casting seams of the cylinder.

13.24 Install rear manifold clamp.

A Torque to 11 in-lbs. (1 Nm).

603GC SHOP MANUAL

NOTE:

Insure that the intake boot is properly installed.

DO NOT OVER TIGHTEN INTAKE BOOT CLAMP.

If over tightened, intake boot can tear, resulting in an air leak which will cause engine damage.

13.25 Install protective spring onto pulse tube.

13.26 Install the pulse tube onto cylinder barb.

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603GC SHOP MANUAL

13.27 Install carburetor base.

13. CYLINDER & PISTON

A S

B S

lip pulse tube into carburetor base.

lip rear manifold into carburetor

base.

C M

ake sure rear manifold lip is flat.

13.28 Install carburetor base screws.

A Use Loctite® 242 on screws (3).

B M

ake sure to include stop switch wire

on front screw.

C Torque to 35 in-lbs. (4 Nm).

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Page 54

14. WATER HOSE

14 This section covers water hose

and side cover.

14.1 Inspect water hose and side cover.

A Replace if damaged.

14.2 Assemble in reverse order.

14.3 Remove water hose connector from side cover.

A Remove clamp and hose from fitting.

603GC SHOP MANUAL

B Unthread fitting from side cover.

14.4 Inspect side cover for damage.

A Replace if necessary.

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603GC SHOP MANUAL

15 This section covers the removal,

inspection, and installation of the ignition coil. Removal of the starter is required. Refer to section 8 if necessary.

15.1 Remove starter flywheel shroud by

unhooking wires.

15.2 Remove ignition coil screws, wave

washers and plain washers.

15.3 Remove ignition coil.

15. IGNITION COIL

15.4 Inspect ignition coil.

ook for:

A L

• Cracks

• Missing insulation

• Wear marks in wire

B Clean flywheel magnets and

coil if rusty.

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Page 56

15. IGNITION COIL

15.5 Install Ignition coil.

603GC SHOP MANUAL

A Place ignition coil shim (0.012”)

on magnet counterweight side of flywheel.

B Set ignition coil in place. C Install ignition coil screws, wave

washers, and plain washers with Loctite® 242.

Holding shim, rotate flywheel magnet

around to coil.

E Torque ignition coil screws to

26 in-lbs. (3 Nm).

F R

emove shim, rotate flywheel to

check clearance.

15.6 Install flywheel shroud.

15.7 Route yellow ignition stop switch wire through crankcase into carburetor chamber.

15.8 Complete ignition wire routing.

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603GC SHOP MANUAL

16 This section covers the removal,

inspection, and installation of the flywheel. Removal of spark plug and the starter is required. Refer to sections 6 and 8 if necessary.

16.1 Insert piston stop.

16.2 Remove flywheel nut, wave washer,

and plain washer.

16. FLYWHEEL

16.3 Screw on flywheel removal tool finger

tight. Unscrew tool 1 ½ turns leaving approximately 1/8 inch (5 mm) space between tool and flywheel.

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Page 58

16. FLYWHEEL

16.4 Using pliers, hold saw up by magnet counterweight.

16.5 Strike flywheel removal tool with a ball peen hammer. The flywheel should release from crankshaft.

16.6 Inspect and clean flywheel. Replace if any of the fins are broken.

603GC SHOP MANUAL

16.7 Inspect cast woodruff key inside the flywheel.

NOTE:

Key is cast into flywheel.

16.8 Install flywheel, plain washer, wave washer, and flywheel nut.

A Torque nut to 217 in-lbs. (25 Nm).

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603GC SHOP MANUAL

17 This section covers the removal,

inspection, and installation of the front handle.

17.1 Remove front handle screws on

right side.

17. FRONT HANDLE

17.2 Remove front handle screws

on bottom.

17.3 Install front handle.

A R

oll front handle into place.

B Install front handle screws (4).

C Use Loctite® 242.

D Torque to 69 in-lbs. (8 Nm).

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Page 60

18. FUEL TANK

18 This section covers the

disassembly, inspection, and assembly of the vibration isolaters, fuel tank, and rear handle.

18.1 Remove vibration isolator screws (2) and wave washers on clutch side of saw.

603GC SHOP MANUAL

18.2 Remove vibration isolator screws (2) and wave washers on flywheel side of saw.

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603GC SHOP MANUAL

18.3 Separate crankcase and fuel tank.

NOTE: Saws have a rubber water

deflector connected to the 2 bottom vibration isolators on the clutch side (circled).

18.4 Remove vibration isolators (4) from

fuel tank if necessary.

18. FUEL TANK

18.5 Assemble in reverse order.

NOTE: During assembly be careful to

avoid kinking the fuel line.

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Page 62

19. CRANKCASE

19 This section covers the

disassembly, inspection, and assembly of the crankcase seals and crankshaft bearings.

19.1 Remove outer crankshaft seal housing screws and wave washers.

603GC SHOP MANUAL

19.2 Remove crankcase bolts (5).

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603GC SHOP MANUAL

19.3 Heat the flywheel side crankcase

with heat gun for 5 minutes, approximately 150° F (65.5° C).

19.4 Remove the flywheel side crankcase

– tap crankshaft with plastic mallet.

19. CRANKCASE

A S

uspend above work surface.

B Tap with mallet.

NOTE: A nut should always be placed

on a threaded shaft when pounding or pressing on it.

19.5 Remove the flywheel side crankcase

seal with 1/2” (13 mm) socket.

Page 64

19. CRANKCASE

19.6 Disassembly of crankcase.

Heat the clutch side crankcase with

heat gun to 150° F (65.5° C).

19.7 Remove crankshaft from the clutch-side crankcase tap crankshaft with a plastic mallet.

603GC SHOP MANUAL

A Suspend above work surface.

B Tap with plastic mallet.

19.8 Remove the bearing from the flywheel side of crankshaft.

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603GC SHOP MANUAL

19.9 Remove the bearing, seal, and

bushing from the clutch side of crankshaft.

19.10 Assembly of crankcase.

A Clean mating crankcase faces.

19.11 Heat crankcase halves to 150° F.

19. CRANKCASE

19.12 Install bearing into crankcase halves.

19.13 Tap with bearing driver and mallet.

Page 66

19. CRANKCASE

19.14 Repeat with other half.

19.15 Install crankshaft into clutch side of case.

603GC SHOP MANUAL

19.16 Place clutch side crankcase seal on crankshaft.

A Tap lightly with bearing driver

and mallet.

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603GC SHOP MANUAL

19.17 Coat crankcase gasket with

ICS® 2-stroke engine oil.

19.18 Align crankcase gasket on flywheel

side crankcase pins.

19. CRANKCASE

19.19 Place crankcase halves together and

align crankcase pins.

Page 68

19. CRANKCASE

19.20 Assemble crankcase halves – tap with bearing driver and mallet.

19.21 Install crankcase bolts.

A Use Loctite® 242.

orque to 69 in-lbs. (8 Nm).

B T

603GC SHOP MANUAL

19.22 Install flywheel side crankcase seal – tap with bearing driver and mallet.

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603GC SHOP MANUAL

19.23 Assemble in reverse order

A Install outer crankshaft seal housing

with 3 bolts and use Loctite® 242.

19.24 Trim crankcase gasket flush.

19. CRANKCASE

Page 70

20. BAR STUDS & BAR PAD

20 This section covers the removal

and installation of the bar studs and bar pad.

20.1 On 603GC saws:

NOTE: This requires the removal of the

piston and cylinder, and to split the crankcase. (Refer to section 13 &19 for detailed instructions)

A Remove side cover.

B Remove bar pad cover.

C Split the crankcase.

603GC SHOP MANUAL

D Press out bar studs.

E Assemble in reverse order.

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603GC SHOP MANUAL

21 This section covers the

removal and installation of the chain tensioner.

21.1 Remove bar plate to expose

the chain tensioner.

21.2 Unscrew tensioner to remove.

21. CHAIN TENSIONER

A R

B R

emove tensioner pin.

emove tensioner screw keeper.

21.3 Assemble in reverse order.

NOTE: The tensioner is intended to

perform as a fuse in high load or sudden impact situations. P/N 505393

Page 72

22. CARBURETOR TUNING

603GC SHOP MANUAL

22 This section covers carburetor tuning. Included in this section are basic settings,

idle speed adjustment, and complete adjustment.

The carburetor on a new saw is set at the factory for optimal performance and compliance to EPA Phase 1 emmissions standards. However, minor adjustments may be required in certain conditions, such as high elevation. A replacement carburetor is not set correctly from the factory. Use the tuning instructions in this manual to adjust carburetor to factory-recommended settings. (DO NOT adjust the carburetor for maximum rpm. Adjusting the carburetor for maximum rpm will cause engine damage). Always set the carburetor jets to factory settings

when replacement or complete rebuild becomes necessary.

NOTES:

• These cut-off saws are equipped with an electronic speed limiter, as part of the ignition system. This will prevent the saw from going above 12,500 rpm. Attempting to set the carburetor mixture to increase the speed or power beyond this limit may seriously damage the engine.

• Always check the air filter, pre filter, fuel filter, and spark plug before making carburetor tunings and clean or replace if necessary

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603GC SHOP MANUAL

22. CARBURETOR TUNING

22.1 Basic Setting -

H = 1 turn from closed

L = 1 turn from closed

Complete carburetor readjustment.

22.2 Remove limiter cap.

A L

ook into adjustment screw hole. Observe orientation of the release slots on the adjustment screw limiter cap.

RPM Settings for saws.

NOTE: Saw tuned without bar and chain installed.

Idle Speed = 3,000 ± 500 rpm

Full Throttle = 12,500 ± 500 rpm

B Insert the limiter cap puller blades

into the release slots.

C F

irmly hold the tool shaft while screwing in the puller screw until the screw head is against the puller shaft.

D U

nscrew the puller screw.

Page 74

22. CARBURETOR TUNING

22.3 Using a 5/64” straight blade screwdriver, gently turn the adjustment screws clockwise until completely closed.

22.4 Set the adjustment screws at the Basic Setting:

H = 1 turns from closed

L = 1 turns from closed

The side cover must be held

tightly in place with the side cover nuts, using a bar and no chain. Failure to do so may result in personal injury.

22.5 Start the saw and warm up the engine.

22.6 With a tachometer check the saw rpm, with bar and no chain:

603GC SHOP MANUAL

A Idle = 3,000 ± 300 rpm

B If the idle rpm does not fall into this

range, adjust the T screw, clockwise to raise RPM, counterclockwise to lower RPM.

22.7 With a tachometer check the saw full throttle rpm, with no bar and chain:

A Target = 11,000 ± 500 rpm

22.8 If the full throttle rpm falls below this range, turn the H screw in (clockwise) 1/16th of a turn at a time.

A Pulse the throttle to help stabilize

the system.

Do not hold the saw at max

rpm for more than 5 seconds or cylinder damage could occur.

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603GC SHOP MANUAL

22.9 When the carburetor is adjusted

correctly set the limiter caps as shown with a 1/4” straight blade screwdriver.

22. CARBURETOR TUNING

A L

B H

= vertical

= horizontal

Page 76

23. IDLE SPEED ADJUSTMENT

23 This section covers idle speed

adjustment.

23.1 If engine stops while idling:

A Make sure the chain is

properly tensioned.

B Turn T screw clockwise until

chain begins to move.

C Back T screw out ½ turn.

23.2 If chain turns at idle:

603GC SHOP MANUAL

A B

ack T screw out until chain

stops moving.

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603GC SHOP MANUAL

24. DIAGRAMS

24 This section provides several flowcharts to aid diagnosing common problems.

CHECK POSSIBLE CAUSE REPAIR

• Clean or replace the air filter.

The engine runs rough at

all speeds.

YES

• Dirty or clogged air filter.

• Water has been ingested.

• Loose or dirty spark plug.

• Inspect air intake sysetm for water.

• Inspect fuel system for water.

• Tighten, clean, or replace

spark plug.

A dirty air filter is the #1 reason for engine problems.

The engine is overheating.

Poor acceleration.

Uneven idle or engine

may “run away”.

YES

• Operator is overworking

the saw.

• Carburetor mixture is

too lean.

• Incorrect fuel/oil ratio.

• Flywheel fins are clogged.

• Air deflector is missing.

• Cylinder fins are clogged.

• Dirty or clogged air filter.

• Clogged fuel filter.

• Incorrect carburetor tune.

• Plugged tank breather.

• Blocked pulse tube.

• Air leak at intake boot,

cylinder gasket, or crankcase gasket.

• Faulty carburetor

diaphragm.

• See Operator’s Manual.

• See Carburetor Tuning section.

• See Saw Specifications section.

• Clean flywheel fins with

wire brush.

• See Starter Cover section.

• Clean cylinder fins.

• Clean or replace the air filter.

• Replace fuel filter.

• See Carburetor Tuning section.

• Repair or replace fuel tank

breather.

• Replace pulse tube.

• Inspect air intake boot.

• Pressure test crankcase.

• Replace carburetor.

Diamond chain

moves at idle.

Excessive vibration.

YES

• Idle speed too high.

• Broken clutch spring.

• Damaged shock absorber.

• Damaged or broken

flywheel fins.

• Bent crankshaft.

• Adjust idle speed.

• Replace clutch spring.

• Replace shock absorbers.

• Replace flywheel.

• Replace crankshaft.

Page 78

24. DIAGRAMS

603GC SHOP MANUAL

Saw Will Not Start

CHECK POSSIBLE CAUSE REPAIR

Does the engine crank?

YES

Is there spark?

YES

Is the spark plug firing

properly?

YES

Insure cylinder

compression is above

125 psi.

• Dirty or broken recoil

starter.

• Internal damage.

• The ignition switch is

“OFF”.

• Faulty ignition ground.

• Faulty spark plug lead.

• Faulty ignition coil.

• Plug is soaked with fuel.

• The plug is fouled or

gapped improperly.

• Plug is internally faulty or

the wrong type.

• Loose spark plug.

• If below 125 psi – excess

wear on the piston, cylinder, rings.

• Clean, rebuild or replace the

recoil starter.

• Inspect for internal damage such

as seized piston.

• Move switch to “ON” and re-test.

• Tighten connections or replace

ground wire.

• Repair or replace spark plug lead.

• Replace ignition coil.

• Dry plug, expel excess fuel from

cylinder and crankcase.

• Clean and re-gap the plug to

0.020 inch (0.05 mm).

• Replace with the correct plug –

see Spark Plug Reference Guide.

• Tighten plug and re-test.

• Replace piston and cylinder.

YES

Is the fuel fresh?

Is the fuel mixed 50:1?

YES

Is the fuel reaching the

carburetor?

YES

Is too much fuel

reaching the

carburetor?

Is the flywheel key

sheared?

YES

• Fuel is old, varnished, or

contaminated.

• Clogged fuel filter.

• Damaged fuel line.

• Damaged pulse tube.

• Plugged fuel tank

breather.

• Carburetor is tuned

incorrectly.

• Plugged fuel tank breather.

• Loose flywheel. • Replace key and reinstall flywheel.

• Empty tank and re-fill with fresh

fuel of the correct mixture (25:1).

• Replace fuel filter.

• Replace fuel line.

• Replace pulse tube.

• Repair or replace fuel tank

breather.

• Refer to Carburetor Tuning

section.

• Repair or replace fuel tank

breather.

Page 79

603GC SHOP MANUAL

25 This section covers testing the

fuel system for leaks. Engine starvation can result from a leak or malfunction of any of the main components of the fuel system. The five main components are the fuel tank, fuel tank breather, fuel filter, delivery tubes, and carburetor.

25.1 Remove and inspect the fuel filter.

25. FUEL SYSTEM LEAKS

A R

25.2 Test the main fuel pick-up tube

A Connect tube to the pressure gauge

B Pressurize the tube to 7 psi (0.5 bar).

eplace the fuel filter if there is any foreign material in the felt or the internal screen.

for leaks.

and to the fuel line.

C If the pressure does not maintain,

separate the fuel line from the carburetor.

Page 80

25. FUEL SYSTEM LEAKS

D Plug one end of the main fuel

pick-up tube.

603GC SHOP MANUAL

E R

e-pressurize the tube to

7 psi (0.5 bar).

F R

eplace the tube if pressure is

not maintained.

G I

f the main fuel pick-up tube does maintain pressure, then the leak has been isolated to the carburetor. Refer to the Walbro Diaphragm Carburetor Service Manual.

25.3 The fuel tank breather stabilizes the pressure in the fuel tank preventing both excessive pressure, which could flood the engine, and negative pressure, which could starve the engine of fuel.

25.4 Fuel tank breather is located inside the air filter compartment.

25.5 Testing the fuel tank breather.

A Attach the pressure gauge and bulb

to the fuel tank breather. Pressurize the tube to 7 psi (0.4 bar).

B The pressure should reduce to nearly

0 psi (0 bar) over about 3 seconds.

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603GC SHOP MANUAL

25.6 If the pressure does not reduce

to 0 psi, disassemble or replace the breather.

A Disassemble by snapping off cap.

25. FUEL SYSTEM LEAKS

B Clean parts with solvent or fuel

25.7 Assemble in reverse order.

A Make sure duck bill opens easily.

B Make sure that the spring taper is

oriented in the correct direction.

C Assemble by snapping cap in place.

Page 82

26. CRANKCASE LEAKS

26 This section covers testing the

crankcase for leaks. A leak in the crankcase can cause the engine not to run.

26.1 Install the intake seal flange.

A Plug cylinder pulse tube.

26.2 Install the exhaust seal flange.

26.3 Block one of the flange tubes with a rubber plug.

603GC SHOP MANUAL

26.4 Install the pressure gauge and bulb.

26.5 Pressurize the crankcase to 7 psi (0.5 bar).

26.6 If the pressure does not remain the same, use soapy water to find the leak.

NOTE: It is recommended that this

test be performed after an engine rebuild.

Page 83

603GC SHOP MANUAL

APPENDIX

1 The Spark Plug Reference Guide is to be used as a guide only. When trying

a plug from a different manufacturer, perform a plug check to be sure that the plug will work.

SPARK PLUG REFERENCE GUIDE

ICS RESISTOR CHAMPION

RESISTOR

73199

RCJ7Y BPMR7A WSR7F

NGK RESISTOR BOSCH RESISTOR

Page 84

603GC SHOP MANUAL

Page 85

ICS, Blount Inc. 4909 SE International Way Portland, Oregon 97222

TEL 800-321-1240 FAX 503-653-4393

www.icsbestway.com

p/n 71537