Echo CS-3700ES Mounting instructions

CS-3700ES, CS-4200ES01-36C-01 1
INTRODUCTION
We are constantly working on technical
improvement of our products. For this reason,
technical data, equipment and design are
subject to change without notice. All
specifications, illustrations and directions in
this SERVICE DATA are based on the latest
products information available at the time of
publication.
ECHO SERVICE MANUAL Ord. 401-
21(Model : CS-4200, CS-4400) contains lots
of information for servicing this model.
Introduction of primer and carburettor change
on CS-3700ES are informed by Technical
Information No. 2006-324.
0
CONTENTS
page
1 SERVICE INFORMATION ............................. 2
1-1 Specification ............................................... 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 EMISSION ADJUSTMENT GUIDE ............... 7
2-1 General adjusting rules .............................. 7
2-2 Presetting idle adjust screw, L mixture needle
and H mixture needle ....................................... 8
2-3 Adjusting carburettor.................................. 9
Reference No. 01-36C-01
REVISED: 200607
INDEX
ISSUED: 200409

SERVICE INFORMATION CS-3700ES CS-4200ES
2
1 SERVICE INFORMATION
1-1 Specifications
Model CS-3700ES CS-4200ES
Dimensions Length* mm(in) 383 (15.1)
Width mm(in) 238 (9.4)
Height mm(in) 270 (10.6)
Dry weight* kg(lb) 4.4 (9.7)
Engine Type KIORITZ, air-cooled, two-stroke, single cylinder
Ventilated piston
Rotation Clockwise as viewed from the output end
Displacement cm3(in3) 35.8 (2.19) 39.6 (2.42)
Bore mm(in) 39 (1.54) 41 (1.61)
Stroke mm(in) 30 (1.18) 30 (1.18)
Compression ratio 7.4 7.45
Carburettor Type Diaphragm horizontal-draught with auto-return choke
Model WT-416C Walbro WT-594
Walbro WT-812 with primer**
Venturi size-Throttle bore mm(in) 13.5 - 15.85 (0.532 - 0.624)
Ignition Type CDI (Capacitor discharge ignition) system
Spark plug BPMR7A RCJ6Y
Starter Type ES (Effortless-start)
Rope diameter x length mm(in) 3.0 x 830 (0.12 x 32.7)
Fuel Type Premixed two-stroke fuel
Mixture ratio 50 : 1 (2 %)
Petrol Minimum 89 octane petrol (RON)
Two-stroke air cooled engine oilISO-L-EGD (ISO/CD13738), JASO FC
Tank capacity L (U.S.fl.oz.) 0.41 (13.9)
Clutch Type Centrifugal, 3-shoe slide with 3-tension spring
Guide bar / Saw chain lubrication type Automatic with volume adjuster
Oil Tank capacity L (U.S.fl.oz.) 0.24 (8.1)
Sprocket Type Spur
Number of teeth 7
Pitch in 0.325
Cutting devices
Guide bar Type 33RD58-325 38RD58-325 43RD58-325
Called length cm 33 38 43
Gauge in 0.058
Saw chain Number of drive links 56 64 72
Pitch in 0.325
Gauge in 0.058
* Without guide bar and saw chain.
** Primer is installed on switch bracket since serial number 36008701 on CS-3700ES.

SERVICE INFORMATION
CS-3700ES
CS-4200ES 3
1-2 Technical data
Model CS-3700ES CS-4200ES
Engine
Idling speed r/min 2300 - 3000
Operating speed* r/min 8500 - 9000
High speed (No load full throttle)* r/min 11500 - 12500
Clutch engagement speed* r/min 3500 - 4300
Compression pressure MPa (kgf/cm2) (psi) 1.0 (10) (145) 1.15 (11.5) (165)
Ignition system
Spark plug gap mm(in) 0.6 - 0.7 (0.024 - 0.028)
Minimum secondary voltage at 1000 r/min kV 15
Secondary coil resistance kΩ1.7 - 2.2
Pole shoe air gaps mm(in) 0.35 - 0.45 (0.014 - 0.018)
Ignition timing at 1500 r/min °BTDC 25
Carburettor WT-416C WT-812 WT-594
Idle adjust screw initial setting turns in** 1 1/8 1 3/4 1 3/8
L mixture needle initial setting turns back 1 1/4 1 1/4
H mixture needle initial setting turns back 3 3 1/2 2 5/8
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
Chain oil discharge volume at 7000 r/min Adjustable : 1.5 - 13 (0.05 - 0.40)
mL/min(U.S.fl.oz./min) (Factory set 7 mL/min)
BTDC: Before top dead centre.
*With 38cm guide bar and saw chain.
**Set idle adjust screw to contact throttle plate before initial setting.

SERVICE INFORMATION CS-3700ES CS-4200ES
4
1-3 Torque limits
Descriptions Size kgf•cm N•m in•lbf
Starter Starter pawl M5* 40 - 60 4 - 6 35 - 50
system Starter case M4 10 - 20 1 - 2 9 - 18
Ignition Magneto rotor (Flywheel) M8 200 - 240 20 - 24 175 - 210
system Ignition coil M5 50 - 75 5.0 - 7.5 45 - 65
Spark plug M14 150 - 170 15 - 17 130 - 150
Fuel Carburettor M5 25 - 35 2.5 - 3.5 22 - 30
system Intake bellows M5 30 - 45 3.0 - 4.5 26 - 40
Clutch Clutch hub LM10 300 - 400 30 - 40 260 - 350
Engine Crankcase M5*†70 - 110 7 - 11 60 - 95
Engine mount M5 70 - 110 7 - 11 60 - 95
Muffler M5 70 - 100 7 - 10 60 - 90
Others Auto-oiler M4 15 - 25 1.5 - 2.5 13 - 22
Front handle M5** 45 - 65 4.5 - 6.5 40 - 55
Cushion Front M5 30 - 40 3 - 4 26 - 35
Rear M4 35 - 50 3.5 - 5 30 - 45
Brake lever (Hand guard) M5 25 - 45 2.5 - 4.5 22 - 40
Chain catcher M5** 20 - 40 2 - 4 18 - 35
Guide bar M8 200 - 230 20 - 23 175 - 200
Regular bolt, nut, and screw M3 6 - 10 0.6 - 1 5 - 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
1-4 Special repairing materials
Material Location Remarks
Adhesive Ball bearing outer / crankcase Loctite #675 or equivalent
Cushion (Small : 4pcs) Loctite #424 or equivalent
Liquid gasket Crankcase seams Loctite #515 or equivalent
Thread locking sealant Starter pawl screws Loctite #242, ThreeBond 1324 or equivalent
Grease Auto-oiler worm
Clutch needle bearing
Rear handle cushion Lithium based grease
Rewind spring
Starter center shaft
Chain brake (metal contact part) Molybdenum grease (approx. 1 gram)
LM: Left-hand thread *Apply thread locking sealant (See below) ** Tapping screw
†The torque differences among four bolts should not exceed 20 kgf•cm (2N•m, 17in•lbf) on one cylinder or
crankcase.

SERVICE INFORMATION
CS-3700ES
CS-4200ES 5
5K1775K177 5K083 5K084 5K081
5K082 5K016 5K025
5K174
5K178
5K173
123
4567
5K171 5K191B
1-5 Service Limits
mm (in)
A Cylinder bore When plating is worn and aluminium can be seen
B Piston outer diameter Min. 38.91 (1.53) 40.94 (16.12)
C Piston pin bore Max. 9.030 (0.356)
D Piston ring groove Max. 1.6 (0.063)
E Piston ring side clearance Max. 0.1 (0.004)
F Piston pin outer diameter Min. 8.98 (0.353)
G Piston ring width Min. 1.45 (0.057)
H Piston ring end gap Max. 0.5 (0.02)
K Con-rod small end bore Max. 12.125 (0.477)
L Crankshaft runout Max. 0.05 (0.002)
M Sprocket bore Max. 12.98 (0.511)
N Clutch drum bore Max. 71.5 (2.81)
P Sprocket wear limit Max. 0.5 (0.02)
ABCD
FGH
LMP
N
E
K

SERVICE INFORMATION CS-3700ES CS-4200ES
6
1.35
0.4
1.65
1.5
a
20
20
40
40
60
60
80
80
120
120
140
140
160
160
180
180
20
20
100
100
91019
1-6 Special tools
145 2
69
10 11 1312
14 15 16 19
3
8
Key Part Number Description Used for:
1 897801-33330 Tachometer PET-1000 Measuring engine speed to adjust carburettor
2 895612-79920 L-hex wrench (3 mm) Removing and installing hex. socket bolt (M4)
3 895610-79920 L-hex wrench (4 mm) Removing and installing hex. socket bolt (M5)
4 897501-03938 Puller Removing magneto rotor
5 897505-16133 Clutch tool Removing and assembling clutch assembly
6 897537-30130 Piston stopper Locking crankshaft rotation
7 897563-19830 Metering lever gauge Measuring metering lever height on carburettor
8 897702-30131 Piston pin tool Removing and installing piston pin
9 897603-23030 PTO shaft puller Removing PTO shaft
10 897708-19835 Worm puller Removing auto-oiler worm
11 Y089-000010 Worm inserter Installing auto-oiler worm
12 897724-01361 Spring pin tool Removing and installing spring pin (4 mm or 5/32 in dia.)
13 897726-09130 Oil seal tool Installing oil seals
14 897800-79931 Spark tester Checking ignition system
15 897803-30132 Pressure tester Testing carburettor and crankcase leakage
16 897826-16131 Pressure rubber plug Plugging intake port to test crankcase / cylinder leakages
17 897827-16131 Pressure plate Plugging intake port to test crankcase / cylinder leakages
18 91007 Compression gauge Measuring cylinder compression
19 91019 Limiter cap tool Removing and installing limiter cap
a = 3 mm
a = 4 mm
7
18
17

SERVICE INFORMATION 7
CS-3700ES
CS-4200ES
H
L
B
AA
B
2 EMISSION ADJUSTMENT GUIDE
2-1 General adjusting rules
A. Before starting the unit for adjustment, check the following items.
1. The correct spark plug must be clean and properly gapped.
2. The air filter element must be clean and properly installed.
3. The muffler exhaust port must be clear of carbon.
4. The fuel lines, tank vent and fuel filter are in good condition and clear of debris.
5. The fuel is fresh ( > 89 octane : RON) and properly mixed at 50 : 1 with “ISO L-EGD” or “JASO-FC” 2-
stroke oil.
6. The recommended bar and chain must be installed, and properly tensioned.
NOTE : In order to achieve proper carburettor adjustment, 38 cm bar and chain should be installed on the
unit. Otherwise serious engine damage will occur due to overspeeding.
B. Set L and H mixture needles full anticlockwise. Start and run engine for two minutes alternating engine
speed between WOT and idle every 5 seconds. Adjust idle speed screw to 2,700 +/- 200 r/min. Adjust H
mixture needle to 12,000 +/- 500 r/min. If engine does not run correctly after this adjustment, proceed to
the next step 2-2.
IMPORTANT : After adjusting carburettor according to the steps 2-2 and 2-3, the limiter cap(s) must
be installed on L and H mixture needle(s) to comply with Emission Directive.
2-2 Presetting idle adjust screw, L mixture needle and H mixture needle
1. Turn the L and H mixture needles anticlockwise
to rich side stop to align limiter cap tab (A) with
locating slot (B), using 2.5 mm blade screwdriver.
NOTE : If cap tabs (A) misalign with locating slots
(B), there is a chance to strip thread.
(continued)

SERVICE INFORMATION
8CS-3700ES
CS-4200ES
2-2 Presetting idle adjust screw, L mixture needle and H mixture needle (continued)
2. Screw threaded end of limiter cap tool 91019 with
2.5 mm left-hand thread into center hole of limiter
cap anticlockwise until tab of the limiter cap just
comes out of the locating slot.
NOTE : DO NOT COMPLETELY REMOVE LIMITER
CAP FROM CARBURETOR!
If the limiter cap was pulled out completely, there
is a chance that the other mixture needle would turn
and limiter cap tab would misalign with locating slot
when screwing the limiter cap removal tool into
center hole of the limiter cap.As a result, the thread
of the limiter cap would be stripped. Use 3 mm
diameter thread of wood screw to remove the
stripped limiter cap.
3. Remove the limiter cap removal tool from the
limiter cap by turning the tool clockwise, leaving the
limiter cap in place.
4. Screw threaded end of limiter cap removal tool
91019 into center hole of the other limiter cap
anticlockwise until the limiter cap is removed from
the mixture needle completely. Remove the limiter
cap from limiter cap removal tool turning clockwise,
and screw thread of limiter cap removal tool 91019
into center hole of previous limiter cap to pull out
completely.
5. Turn L and H mixture needles clockwise until
lightly seated, and then turn out both mixture needles
following turns.
L mixture needle : 1 1/4
H mixture needle : 3 (CS-3700ES:3600001 - 36008700)
3 1/2 (CS-3700ES:36008701 and after)
2 5/8 (CS-4200ES)
NOTE : If needles are forced during seating, damage
to carburetor may occur.
6. Remove air filter cover and air filter to see that
idle adjust screw contacts the throttle plate. Turn
idle adjust screw anticlockwise and set the screw
until the tip just contacts the throttle plate. Then turn
idle adjust screw 1 1/8 (CS-3700ES : Serial Number
36000001 - 36008700),1 3/4(CS-3700ES: Serial
Number 36008701 and after), 1 3/8(CS-4200ES)
turns clockwise. Reinstall air filter, and air filter cover.

SERVICE INFORMATION 9
CS-3700ES
CS-4200ES
H
L
A
B
B
A
H mixture needle
L mixture needle
Idle adjust screw
C
2-3 Adjusting carburetor
1. Start engine and warm it up at idle for one minute.
Turn H mixture needle anticlockwise until engine
speed drops to approx. 11,000 r/min.
2. Warm it up well for 100 sec with cycle of 5
seconds at WOT (Wide Open Throttle) and 5
seconds at idling.
NOTE : Do not run engine at high speed without
load longer than 5 seconds, or engine damage may
occur.
3. Adjust L mixture needle with 2.5 mm blade
screwdriver to reach maximum engine speed just
before lean drop off.
4. Set idle engine speed to 3,700 r/min by turning idle adjust screw. Engine speed should be stable at
3,700 +/- 10 r/min after idle adjust screw adjustment.
5. Turn L mixture needle anticlockwise reducing engine idle speed 1,000 r/min to set idle speed at 2,700
r/min. The engine idle speed range is 2,500 - 2,900 r/min.
NOTE : Engine speed must be allowed to stabilize a minimum of 20 seconds after each adjustment of L
mixture needle to assure accurate tachometer readings.
6. Make sure WOT engine speed is approx. 11,000 r/min. If WOT engine speed is over 11,500 r/min, turn
H mixture needle anticlockwise until engine speed drops to approx. 11,000 r/min. Turn H mixture needle
1/8 turn increments clockwise at idle engine speed, then squeeze throttle trigger and check WOT engine
speed. If the WOT engine speed is less than 11,500 r/min, turn H mixture needle 1/8 turn clockwise again,
and check WOT engine speed. The final WOT engine speed should fall within the11,600 to 12,400 r/min
range.
7. After adjusting carburettor, screw new limiter cap
on the limiter cap removal tool 91019 (C)
anticlockwise approx. 2 turns as shown, and put the
limiter caps on L and H mixture needles respectively
and remove the limiter cap tool.And then press the
caps on L and H mixture needles with bar tool.
NOTE : Align the limiter cap’s tabs (A) with locating
slots (B) in extended housing of carburettor.
IMPORTANT : The limiter caps must be installed L and H mixture needles to comply with Emission
Directive.
8. Start engine, and verify engine idle speed ranges from 2,300 to 3,000 r/min, and WOT engine speed
ranges from 11,500 to 12,500 r/min. Make sure chain does not rotate when engine is idling. When final
adjustment is completed, the engine should idle, accelerate smoothly, and attain WOT per above
specification.
NOTE : Initial carburettor setting (idle adjust screw, L and H mixture needles) shown on page 3 and 8 is
to start the engine after restoration or carburettor change. Idle adjust screw, idle and H needles turn for
designated engine revolution through procedures indicated here may vary.As long as idle and WOT engine
speed is set in given range, variance would be ignorable.