Echo shindaiwa CS-501SX User manual

Ref. No. 401-42
CS-501SX
CS-501SXH
ECHO:
shindaiwa:
501sx
(Serial number: 37000001 and after)
(Serial number: 38000001 and after)
Copyright C 2019 YAMABIKO Corporation All rights reserved.

INTRODUCTION
This service manual contains information for ser-
vice and maintenance of ECHO CHAIN SAW,
model CS-501SX,CS-501SXH, shindaiwa
CHAIN SAW, model 501sx.
For systematic diagnosis, to avoid extra work,
time loss and to meet Emission regulation,
please refer to “Troubleshooting guide” that
describes problems, testing, remedies and
references. We recommend you make use of
Operator’s Manual and Parts Catalogue together
with this manual when servicing.
We are constantly working on technical improve-
ment of our products. For this reason, technical
data, equipment and design are subject to
change without notice. All specifications, illustra-
tions and directions in this manual are based on
the latest product information available at the
time of publication.
NOTE: This service manual contains pictures
with different model name for other markets and
different colored model.

TABLE OF CONTENTS
CS-501SX, CS-501SXH
501sx 1
Page Page
1 SERVICE INFORMATION.....................................2
1-1 Specifications...................................................2
1-2 Technical data ..................................................3
1-3 Torque limits.....................................................4
1-4 Special repairing materials...............................4
1-5 Service Limits...................................................5
1-6 Special tools.....................................................6
2 STARTER SYSTEM..............................................7
2-1 Disassembling starter assembly.......................8
2-2 Replacing starter rope......................................9
2-3 Assembling starter..........................................10
2-4 Replacing starter pawl....................................12
3 IGNITION SYSTEM.............................................13
3-1 Troubleshooting guide....................................14
3-2 Testing spark..................................................15
3-3 Inspecting spark plug .....................................15
3-4 Inspecting ignition switch................................16
3-5 Replacing ignition switch................................16
3-6 Inspecting ignition coil resistance...................17
3-7 Replacing spark plug cap and coil..................18
3-8 Replacing ignition coil.....................................18
3-9 Setting pole shoe air gaps..............................19
3-10 Inspecting flywheel and key ...........................19
4 FUEL SYSTEM ...................................................21
4-1 Inspecting air filter..........................................22
4-2 Inspecting fuel cap and fuel strainer...............22
4-3 Inspecting fuel tank and line...........................23
4-4 Inspecting and replacing tank vent.................24
4-5-1 Replacing fuel line..........................................26
4-5-2 Replacing fuel vent pipe.................................27
4-6 Adjusting carburetor.......................................28
4-6-1 General adjustment rules...............................28
4-6-2 Initial setting Throttle adjust screw, L mixture
needle and H mixture needle .........................28
4-6-3 Adjusting carburetor.......................................29
4-7 Air shutter.......................................................30
4-8 Testing carburetor...........................................31
4-9 Inspecting crankcase pulse passage .............32
4-10 Inspecting metering lever height ....................32
4-11 Inspecting inlet needle valve..........................33
4-12 Inspecting diaphragm.....................................33
4-13 Replacing Welch plug.....................................34
4-14 Installing carburetor........................................35
5 CLUTCH SYSTEM..............................................36
5-1 Inspectng clutch parts ....................................37
5-2 Replacing clutch parts....................................38
5-3 Installing clutch assembly...............................38
6 CHAIN BRAKE SYSTEM....................................40
6-1 Disassembling chain brake ............................41
6-2 Assembling brake parts..................................42
7 SAW CHAIN LUBRICATION SYSTEM...............43
7-1 Inspecting oil cap and strainer........................44
7-2 Inspecting auto-oiler assembly and oil line.....45
7-3 Inspecting oil tank vent...................................46
8 ENGINE...............................................................47
8-1 Testing cylinder compression.........................48
8-2 Cleaning cooling air passages .......................48
8-3 Inspecting muffler and exhaust port...............49
8-4 Testing crankcase and cylinder seal...............50
8-5 Inspecting cylinder..........................................51
8-6 Inspecting piston and piston ring....................52
8-7 Replacing oil seal...........................................53
8-8 Disassembling crankcase...............................54
8-9 Replacing ball bearing and oil seal.................54
8-10 Assembling crankshaft and crankcase...........55
8-11 Installing piston...............................................56
8-12 Installing piston ring and cylinder...................57
9 REAR HANDLE AND CONTROL SYSTEM.......58
9-1 Replacing cushions........................................59
9-2 Replacing throttle trigger................................61
9-3 Service hint for heated handle (CS-501SXH only) ...63
9-3-1 Inspecting heated handle...............................64
9-3-2 Replacing stator assembly.............................66
9-3-3 Replacing rear handle heater.........................67
9-3-4 Replacing heater switch.................................69
10 GUIDE BAR MOUNTING SYSTEM..................70
10-1 Replacing chain tensioner..............................71
10-2 Replacing guide bar stud................................71
10-3 Installing guide bar stud .................................72
11 MAINTENANCE GUIDE....................................73
11-1 Disassembly Chart.........................................73
11-2 Troubleshooting guide....................................74
11-3 Service Intervals.............................................76

SERVICE INFORMATION CS-501SX, CS-501SXH
501sx
2
Cutting devices
Guide bar Type V40R21-68AA V45R21-72AA V50R21-80AA
Called length cm 40 45 50
Gauge in 0.058
Saw chain Type Oregon 21BPX, Carlton K2L
Number of drive links 68 72 80
Pitch in 0.325
Gauge in 0.058
1 SERVICE INFORMATION
1-1 Specifications
Models CS-501SX, 501sx CS-501SXH
Dimensions Length* mm(in) 395 (15.6)
Width mm(in) 235 (9.3)
Height mm(in) 290 (11.4)
Dry weight* kg(lb) 4.7 (0.2) 4.9 (10.8)
Engine Type YAMABIKO, air-cooled, two-stroke, single cylinder
Rotation Clockwise as viewed from the output end
Displacement cm3(in3) 50.2 (3.063)
Bore mm(in) 44.0 (1.732)
Stroke mm(in) 33.0 (1.299)
Compression ratio 7.2
Carburetor Type Diaphragm horizontal-draft
Model Walbro WT-1139
Venturi size-Throttle bore mm(in) 13.5 - 15.85 (0.531 - 0.624)
Ignition Type CDI (Capacitor discharge ignition) system
Spark plug NGK BPMR8Y
Exhaust Muffler type Spark arrester muffler
Starter Type Automatic Rewind
Rope diameter x length mm(in) 3.8 x 910 (0.15 x 35.8)
Fuel Type** Mixed two-stroke fuel
Mixture ratio 50 : 1 (2 %)
Gasoline Minimum 89 octane petrol
Two-stroke air cooled engine oilISO-L-EGD (ISO/CD13738), JASO FC/FD
Tank capacity L (U.S.fl.oz.) 0.5 (16.9)
Clutch Type Centrifugal type
Guide bar / Saw chain lubrication type Automatic with volume adjuster
Oil Tank capacity L (U.S.fl.oz.) 0.28 (9.5)
Auto oiler Type Clutch driven type
Sprocket Type Floating rim
Number of teeth 7
Pitch in 0.325
Heated handle --- Equipped
* Without guide bar and saw chain.
** Premixed alkylate fuel for 2-stroke can be used.

SERVICE INFORMATION
CS-501SX, CS-501SXH
501sx 3
1-2 Technical data
Models CS-501SX, 501sx CS-501SXH
Engine
Compression pressure MPa (kgf/cm2) (psi) 0.95 (9.7) (138)
Clutch engagement speed r/min 3,900
Ignition system
Spark plug gap mm(in) 0.6 - 0.7 (0.024 - 0.028)
Spark test Tester gap w/ spark plug mm(in) 4.0 (0.16)
Tester gap w/o spark plug mm(in) 6.0 (0.24)
Secondary coil resistance kΩ2.5 - 2.9
Pole shoe air gaps mm (in) 0.3 - 0.4 (0.012 - 0.016)
Ignition timing at 3,000 r/min °BTDC 20 19
at 8,000 r/min °BTDC 32 30
at 10,000 r/min °BTDC 34 34
Carburetor
Test Pressure, minimum MPa (kgf/cm2) (psi) 0.05 (0.5) (7.0)
Metering lever height mm(in) 1.65 (0.06) lower than diaphragm seat
Tool to adjust mixture needles D-shaped tool (L) P/N X645-000031
(Carb. adjustment tool P/N Y089-000094)
Carburetor adjustment
Before carburetor adjustment : --- Turn off heater switch.
1) Initial setting H mixture needle turn out 3 5/8
L mixture needle turn out 1 3/4
Throttle adjust screw turn in*12 1/8
Engine warm-up Idle - WOT : Total sec. 5 - 5 : 100
2) Find idle maximum speed Adjust L mixture needle to maximum idle speed*2
3) Set idle maximum speed w/ TAS r/min 3,500
4) Set idle speed
by turning L mixture needle CCW r/min 2,700
5) Confirm H mixture needle position
before WOT setting
Turn H mixture needle CCW to confirm engine speed
decreases less than or equal to 12,500 r/min.
6) WOT setting r/min Turn H mixture needle CW in 1/8 turn increments
with the engine at idle, then accelerate to WOT and
check engine speed.The final engine speed should
fall within: 13,000 - 13,800
7) Verify final engine speed with standard equipment Idle: 2,300 - 3,100
r/min WOT: 13,000 - 13,800
8) Verify clutch engagement speed Confirm clutch engagement speed.
If it is less than 1.25 times the idle speed, adjust
the idle speed by turning TAS CCW.
Chain oil discharge volume at 7,000 r/min
mL/min (US.fl.oz./min)
Ajustable: 3.0 - 16.5 (0.12 - 0.65)
(Factory set: 7 mL/min)
BTDC: Before top dead center WOT: Wide open throttle CCW: Counterclockwise TAS: Throttle adjust screw
*1Set Throttle adjust screw to the point that its tip just contacts throttle plate before initial setting.
*2If chain starts to rotate during adjustment process step 2), decrease engine speed by turning TAS CCW
until chain stops and then redo step 2). Repeat this until chain no longer rotates after the adjustment step 2).

SERVICE INFORMATION CS-501SX, CS-501SXH
501sx
4
1-3 Torque limits
Descriptions Size kgf•cm N•m in•lbf
Starter system Starter pawl M5 90 -120 9 -12 80 -105
Starter case M4 20 -30 2 -318
-25
Ignition system Magneto rotor (Flywheel) M8 150 -170 15 -17 130 -150
Ignition coil M4 30 45 3 4.5 25 40
Igniton switch M10 20 -30 2 -318
-25
Spark plug M14 130 -170 13 -17 113 -150
Fuel system Carburetor M5 20 -30 2 -318
-25
Carburetor elbow M4 20 -30 2 -318
-25
Clutch Clutch shoe LM10 280 -300 28 -30 245 -265
Clutch drum M8 150 -170 15 -17 130 -150
Engine Crankcase M5 70 -90 7 -960
-80
Muffler M5 70 -90 7 -960
-80
Cylinder M5 70 -90 7 -960
-80
Cylinder cover M4 25 -35 2.5 -3.5 22 -30
Others Auto-oiler M4 20 -35 2 -3.5 18 -30
Oiler cover M4 30 -45 3 -4.5 25 -40
Crankcase (at oil tank) M5 50 -70 5 -745
-60
Cushion (on Front handle) M5 20 -30 2 -318
-25
Front handle M5 40 -55 4 -5.5 35 -48
M4 30 -45 3 -4.5 25 -40
Rear handle (M side) M5 40 -55 4 -5.5 35 -48
assembly (D side) M5 40 -55 4 -5.5 35 -48
Handle grip M4 20 -30 2 -318
-25
Brake lever (D side) M5 40 -60 4 -635
-40
(M side) M5 50 -70 5 -745
-60
Brake cover M4 10 -20 1 -29
-18
Washer (at brake band) M4 15 -25 1.5 -2.5 13 -22
Sprocket guard plate M4 10 -15 1 -1.5 9 -13
Guide bar nut M8 200 -230 20 -23 175 -200
Chain catcher M5 50 -70 5 -745
-60
Spike M5 50 -70 5 -745
-60
Regular bolt, nut, and screw M3 6 -10 0.6 -15
-9
M4 15 -25 1.5 -2.5 13 -22
M5 25 -45 2.5 -4.5 22 -40
M6 45 -75 4.5 -7.5 40 -65
LM: Left-hand thread
1-4 Special repairing materials
Material Location Remarks
Adhesive Cushion Loctite #406 (424) or equivalent
Grease Auto-oiler worm
EPNOC AP2 (Lithium based grease)
P/N X695-000060
Clutch needle bearing
Choke knob
Oil seal inner lips
Chain brake (metal contact part)
Throttle rod
Bevel gear, Screw, Chain tensioner

SERVICE INFORMATION
CS-501SX, CS-501SXH
501sx 5
1-5 Service Limits
5K177 5K083 5K084 5K081
5K082 5K016 5K025
5K174
5K178
5K173 5K190 5K097
5K097
ABCD
FGH
KLMP
N
E
Description mm (in)
A Cylinder bore When plating is worn and aluminium can be seen
BPiston outer diameter Min. 43. 87 (1.727)
CPiston pin bore Max. 11. 025 (0.4341)
DPiston ring groove Max. 1. 6 (0.063)
EPiston ring side clearance Max. 0. 1 (0.004)
FPiston pin outer diameter Min. 10. 98 (0.4323)
GPiston ring width Min. 1. 45 (0.057)
HPiston ring end gap Max. 0. 8 (0.03)
KCon-rod small end bore Max. 15. 025 (0.5915)
LCrankshaft runout Max. 0. 02 (0.001)
MSprocket bore Max. 12. 75 (0.5020)
NClutch drum bore Max. 73. 5 (2.89)
PSprocket wear limit Max. 0. 5 (0.02)

SERVICE INFORMATION CS-501SX, CS-501SXH
501sx
6
Key Part Number Description Reference
1 897802-33330 Tachometer PET-1000R Measuring engine speed to adjust carburetor
2 897559-02831 T-hex. wrench (4 mm) Removing and installing hex. socket bolt (M5)
3 X602-000230 T-hex. wrench (5 mm) Removing and installing hex. socket bolt (M6)
4 X602-000340 Torx wrench (T27) Removing and installing torx bolt
5 Y089-000111 Puller Removing magneto rotor (flywheel) and crankcase
6 X640-000370 Clutch spanner Removing and installing clutch assembly
7 91004 Module air gap gauge Adjusting pole shoe air gaps
8 91037 Compression gauge Measuring cylinder compression
9 897702-30131 Piston pin tool Removing and installing piston pin
10 897701-02830 Bearing wedge Removing ball bearings on crankshaft
11 897563-19830 Metering lever gauge Measuring metering lever height on carburetor
12 X646-000360 Oil seal tool Installing oil seals and clutch plate
13 897800-79931 Spark tester Checking ignition system
14 897803-30133 Pressure tester Testing carburetor and crankcase leakage
15 Y089-000094 Carburetor adjustment tool Adjusting caburettor
16 500-500 Welch plug tool (Walbro) Removing and installing welch plug
17 X646-000150 Collar oil seal tool Set oil seal collect position
18 91149 Pressure / vacuum tester Testing crankcase / cylinder leakages
19 91041 Pressure rubber plug Plugging exhaust port to test crankcase/cylinder leakages
20 897826-16131 Pressure rubber plug Plugging intake port to test crankcase/cylinder leakages
21 897827-16131 Pressure plate Plugging intake port to test crankcase/cylinder leakages
22 101115-37531 Plug Testing crankcase / cylinder leakages
23 900720-00009 O-ring Testing crankcase / cylinder leakages
1-6 Special tools
12345
678910
11 12 13 14 15
16 17 18
1.35
0.4
1.65
1.5
Ignition Air Gap Gauge
#.014 = .35mm
P/N 91004
0
1
2
3
4
5
6
7
Made in Germany
T27x200
4 01 0 5 5 7 8 6 9 7 4 5
5.0X160
MOLYBDEUMVANADIUM
19 20 22
21 23

STARTER SYSTEM
CS-501SX, CS-501SXH
501sx 7
2 STARTER SYSTEM
(A) Starter case (G) Starter rope
(B) Rope guide (H) Fan cover
(C) Starter grip (J) Starter pawl
(D) Rewind spring (K) Flywheel
(E) Rewind spring case (L) Needle grommet
(F)
Rope reel
(A)
(C)
(B)
(E)
(D)
(F)
(G)
(H)
(K)
(J)
(L)

STARTER SYSTEM CS-501SX, CS-501SXH
501sx
8
WARNING DANGER
Wear eye protection and take care when
removing starter drum. Rewind spring may
unwind suddenly and cause personal injury.
A
B
C
BD
b
2-1 Disassembling starter assembly
1. Remove four screws and remove starter assem-
bly (A) from unit.
2. Pull out starter rope about 30 cm (12 in) and
hold rope reel (B) by hand. Loop excess rope in
rope reel notch (b) as shown.
3. Rotate rope reel (B) counterclockwise to release
tension of rewind spring.
4. Remove bolt (C).
5. Remove rope reel (B) and rewind spring case (D)
with rewind spring.
6. Carefully remove rewind spring and case (D)
as one piece. Rewind spring is under tension and
may release unexpectedly.

STARTER SYSTEM
CS-501SX, CS-501SXH
501sx 9
2-2 Replacing starter rope
1. Pull out and untie knot (A).
2. Pull knot (B) to remove rope from rope reel (C).
4. Make a knot (D) at end of starter rope and pass
the rope through hole of rope reel, then press the
knot (D) into recess as shown.
4K287
3. When installing a new starter rope, singe both
ends of the rope to prevent fraying.
5. Pass the other end of starter rope through
rope guide on starter case, then pass starter rope
through starter grip and make a knot as shown.
6. Tighten knot. Push knot into recess of starter
grip.
D
D
A
B
C

STARTER SYSTEM CS-501SX, CS-501SXH
501sx
10
2. Carefully install rewind spring and case (B) on
starter case (C) as one piece. Match ear (b) and
with ear (c1) on starter case.
3. Assemble rope reel (D) engaging hook (d) with
hook (a) of rewind spring.
NOTE: Apply lithium based grease, ECHO XTend-
ed Protection Lubricant or Red Armor Lubricant on
around startet shaft (c2) of starter case (C) if dry.
4. Check for proper engagement of rewind spring
and rope reel by turning rope reel (D) clockwise
and counterclockwise.
B
A
a
d
D
D
C
B
b
c1
2-3 Assembling starter
1. If rewind spring (A) is removed from spring case
(B), rewind inside case as shown.
c2

STARTER SYSTEM
CS-501SX, CS-501SXH
501sx 11
7. Pull starter several times to check rewind spring
tension. If starter is not rewinding fully, increase
spring tension by rotating rope reel one more turn
clockwise following above step (6).
8. Pull out starter rope all the way, and check that
rope reel can be rotated an additional half or more
turn clockwise as shown, to prevent rewind spring
from breaking.
9. If rope reel can not be turned clockwise, reduce
tension by rotating rope reel counterclockwise one
turn with starter rope hooked at notch (F).
5. Reinstall bolt (E) on starter post.
6. Pull out starter rope inside starter case. Rotate
rope reel clockwise several turns with starter rope
hooked at notch (F) as shown. Hold rope reel to
prevent it from unwinding and pull out starter grip
to take the rope slack.
2-3 Assembling starter (continued)
E
F

STARTER SYSTEM CS-501SX, CS-501SXH
501sx
12
1. Remove starter assembly from unit.
2. Loosen bolt (A) and remove washer, pawl (B),
spacer (C) and torsion spring (D). Replace dam-
aged or worn parts.
NOTE: When it is hard to loosen bolt, install clean
rope (E) in spark plug hole to stop crankshaft rota-
tion and remove bolt easily.
3. Install torsion spring, spacer, pawl, washer and
bolt. To avoid pinching of torsion spring, install
these parts without setting the end (F) of torsion
spring on starter pawl. The bolt is pre-coated with
sealant on the thread. If the sealant is peeled off,
apply thread locking sealant (Loctite #242, Three-
Bond #1324 or equivalent).
4. Using fine wire (G) or appropriate tool, place the
end (F) of torsion spring on pawl (B), by hooking
and passing under pawl as shown. Remove fine
wire or tool.
5. Make sure pawl can move smoothly. If it does
not move smoothly, check parts for correct installa-
tion.
2-4 Replacing starter pawl
D
C
B
A
E
F
F
B
G

IGNITION SYSTEM
CS-501SX, CS-501SXH
501sx 13
3 IGNITION SYSTEM
(A) Flywheel (E) Spark plug cap
(B) Ignition coil (F) Switch lead
(C) Spark plug (G) Ignition switch
(D) Spark plug cap coil
(A)
(B)
(C)
(D)
(E)
(G)
(F)

IGNITION SYSTEM CS-501SX, CS-501SXH
501sx
14
3-1 Troubleshooting guide
Not
OK
Not
OK
Not
OK
OK
OK
OK
Spark plug
Spark
plug cap/
coil
Ignition
switch
Clean /
Regap /
Replace.
Replace.
Start
OK
OK
S.T.
Not
OK
S.T.
Not
OK
Not
OK
S.T.
OK
S.T.
Not
OK Pole
shoe air
gaps
Replace.
Not
OK OK
Not
OK
S.T.
OK
OK
Replace
ignition
coil.
Leads
connections
Not
OK
OK
OK
Not
OK
S.T.
Repair /
Replace.
Not
OK
Remedy
Inspect
Not
OK
Flywheel
key
OK
R.T.*
End
Not
OK
Flywheel
magnet
Replace.
Not
OK
R.T.
Not
OK
OK
OK
Replace ignition coil and / or inspect other
systems.
Replace flywheel.
OK
OK
Adjust pole shoe air gaps.
(Inspect flywheel magnet
at the same time. Go to
Aif OK.)
S.T.
Not
OK
A
S.T.: Spark test.
R.T.: Running test including actual cutting.
OK
OK
Secondary
coil
resist-
ances

IGNITION SYSTEM
CS-501SX, CS-501SXH
501sx 15
3-2 Testing spark
1. Remove cleaner lid, air filter and cylinder cover.
Remove spark plug cap from spark plug.
2. Connect Spark tester 897800-79931 (A) to high
tension lead and connect tester lead (B) on spark
plug.
3. Screw in adjuster (a1) until the needle tips con-
tact. Turn out adjuster (a1) 4 turns to set spark
tester gap (a2) to 4 mm (0.16 in).
4. Turn ignition switch to “I” position. Pull starter
grip several times.
5. If spark is steady blue or white at the tester gap,
ignition system is considered good. Go to inspect-
ing spark plug.
6. If no spark exists or spark is intermittent in
yellow, orange, or red, continue with further inspec-
tion.
DANGER
*Do not test near spark plug hole without
spark plug installed, otherwise there is a
chance to ignite fuel mixture inside cylinder.
*Do not touch metal parts of spark tester
while performing the test to avoid receiving
electrical shock.
*Do not check spark in area where gasoline
is spilled or flammable gases may exist.
3-3 Inspecting spark plug
1. Remove spark plug to inspect for spark plug gap
fouling, cracked or broken insulator, cracked outer
electrode, or rounded center electrode. Replace
spark plug as required.
Spark plug gap (A) standard
: 0.6 to 0.7 mm (0.024 to 0.028 in)
2. If engine does not start with correct spark plug,
inspect if spark plug is wet or dry. If it is exces-
sively wet or dry, inspect fuel system.
B
a1
A
a2
GASO
LINE
A

IGNITION SYSTEM CS-501SX, CS-501SXH
501sx
16
3-4 Inspecting ignition switch
1. Remove cleaner lid, air filter and cylinder cover.
2. Remove switch lead (A) from ignition coil.
3. Connect one probe of Ohm-meter or multi-meter
to switch lead. Connect the other probe to cylinder
fin (B).
4. When ignition switch is in “I” position, tester
should indicate infinite resistance.
5. When ignition switch is in “O (STOP)” position,
tester should show that the circuit is in conducting
state (closed circuit).
6. If ignition switch is defective, replace with a new
one.
A
B
A
B
B
E
C
D
F
G
H
3-5 Replacing ignition switch
1. Remove cleaner lid, air filter and cylinder cover.
2. Remove bolts (A), washers (B) and bolts (C).
3. Remove carburetor elbow (D) and carburetor (E).
4. Loosen nut (F), and remove ignition switch (G)
with switch lead (H) from the unit.
5. Assemble new ignition switch with switch lead
on the unit. Fasten nut (F) on ignition switch.
G

IGNITION SYSTEM
CS-501SX, CS-501SXH
501sx 17
3-6 Inspecting ignition coil resistance
1. Remove cleaner lid, air filter and cylinder cover.
2. Connect one probe of Ohm-meter or multimeter
to spark plug cap coil (A).
3. Connect the other probe to cylinder fin (B) to
measure secondary coil resistance. Secondary
coil resistance should be in the range of 2.5 to 2.9
kΩ.
4. If the meter reading indicates infinite
resistance, remove spark plug cap and spark
plug cap coil, and measure resistance between the
conduction wire of high tension lead and ignition
coil core.
5. If the reading at step 2 or 3 is not in the range of
2.5 to 2.9 kΩ, replace with a new ignition coil (Go
to “3-8 Replacing ignition coil”).
A
B

IGNITION SYSTEM CS-501SX, CS-501SXH
501sx
18
3-8 Replacing ignition coil
1. Remove cleaner lid. Disconnect spark plug cap
from spark plug. Remove cylinder cover.
2. Remove starter assembly and fan cover refer-
ring to “2-1 Disassembling starter assembly“.
3. Disconnect switch lead (A) from ignition coil.
Loosen bolts (B) of ignition coil.
4. Remove ignition coil from cylinder.
5. Remove spark plug cap and spark plug cap coil
from high tension lead (Refer to “3-7 Replacing
spark plug cap and coil”).
6. Install spark plug cap and spark plug cap coil,
switch lead (A) to new ignition coil.
7. Loosely install new ignition coil with two bolts
(B). Set air gap (Refer to “3-9 Setting pole shoe air
gaps“). Tighten two bolts (B). Reinstall fan cover,
starter assembly and cylinder cover.
8. Connect spark plug cap to spark plug. Reinstall
cleaner lid.
3-7 Replacing spark plug cap and coil
1. Disconnect spark plug cap (A) from spark plug.
Remove cap cover from spark plug cap.
2. Apply some oil in spark plug cap (A) for easy re-
moval from high tension lead (B).
3. Pull spark plug cap away from high tension lead.
4. Inspect spark plug cap coil (C) for corrosion
and correct connection. Inspect spark plug cap for
cracks. Replace as required.
NOTE: Make sure spark plug cap coil (C) contacts
center core of high tension lead when reinstalling
it.
5. Coat end of high tension lead (B) with small
amount of oil, and insert it into spark plug cap (A)
as shown, until the spark plug cap coil is properly
seated in the cap.
A
B
C
Coat with small amount of oil
A
B
B