Echo CS-420ES User Manual
01-40B-00
CS-420ES
1
0
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 and directions in this SERVICE
DATA are based on the latest products information available at the time of publication.
INDEX
CONTENTS
1 SERVICE INFORMATION
1-1 Specifi cation ............................................... 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
CARBURETTOR ADJUSTMENT PROCEDURE
2-1 General adjusting rules ............................... 7
2-2 Presetting idle adjust screw, L mixture needle
and H mixture needle ........................................ 7
2-3 Adjusting carburettor................................... 9
2-4 Positioning plug of air cleaner cover ......... 10
Reference No.
.............................. 2
01-40B-00
page
.. 7
ISSUED: 200801
2
1 SERVICE INFORMATION
1-1 Specifi cations
Model CS-420ES
Dimensions Length* mm(in) 393 (15.47)
Width mm(in) 245 (9.65)
Height mm(in) 277 (10.91)
Dry weight* kg(lb) 4.6 (10.1)
Engine Type KIORITZ, air-cooled, two-stroke, single cylinder
Rotation Clockwise as viewed from the output end
Displacement cm
Bore mm(in) 40.0 (1.575)
Stroke mm(in) 32.0 (1.260)
Compression ratio 6.5
Carburettor Type Diaphragm horizontal-draught with auto-return choke
Model Walbro WT-820A
Venturi size-Throttle bore mm(in) 13.50 - 15.85 (0.532 - 0.624)
Ignition Type CDI (Capacitor discharge ignition) system
Digital magneto
Spark plug BPMR8Y
Exhaust Muffl er type Spark arrestor muffl er with catalyst
Starter Type ES (effortless-start)
Rope diameter x length mm(in)
Fuel Type Premixed two-stroke fuel
Mixture ratio 50 : 1 (2 %)
Gasoline Minimum 89 octane gasoline
Two-stroke air cooled engine oil ISO-L-EGD (ISO/CD13738), JASO FC/FD
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.) 0.28 (9.5)
Auto oiler Type clutch driven type
Sprocket Type Spur
Number of teeth 7
Pitch in 0.325
Chain tensioner type Side Access
SERVICE INFORMATION
3
(in3) 40.2 (2.453)
3.0 x 950 (0.12 x 37.4)
CS-420ES
* Without guide bar and saw chain.
Cutting devices
Guide bar Type 38RD58-325 43RD58-325
Called length cm 38 45
Gauge in 0.058
Saw chain Type CARLTON K2L OREGON 21BP
Number of drive links 64 72
Pitch in 0.325
Gauge in 0.058
CS-420ES
1-2 Technical data
Engine
Idling speed r/min 2400 - 2900
Wide open throttle speed* r/min 12300 - 13000
Clutch engagement speed r/min 3800 - 4300
Compression pressure MPa (kgf/cm
Ignition system
Spark plug gap mm(in) 0.6 - 0.7 (0.024 - 0.028)
Minimum secondary voltage at 1000 r/min kV 15
Primary coil resistance Ω 200 - 400
Secondary coil resistance kΩ 1.5 - 2.2
Pole shoe air gaps mm(in) 0.3 - 0.4 (0.012 - 0.016)
Ignition timing at 3000 r/min °BTDC 10
at 8000 r/min °BTDC 32
at 10,000 r/min °BTDC 34
at 12,000 r/min °BTDC 15
Carburettor
Idle adjust screw initial setting turns in** 1 3/8
L mixture needle initial setting turns back 1 3/8
H mixture needle initial setting turns back 2 3/4
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)
SERVICE INFORMATION
2
) (psi) 0.84 (8.6) (122)
3
BTDC: Before top dead centre.
* With 38/45 cm guide bar and saw chain.
**Set idle adjust screw to the point that its tip just contacts throttle plate before initial setting.
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