Echo CS-310 User manual

Ord. No. 401-33
CS-310

INTRODUCTION
This service manual contains information for ser-
vice and maintenance of ECHO CHAIN SAW,
model CS-310.
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.

TABLE OF CONTENTS
CS-310 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................................17
3-6 Inspecting ignition coil resistance...................18
3-7 Replacing spark plug cap and coil..................19
3-8 Replacing ignition coil.....................................19
3-9 Setting pole shoe air gaps..............................20
3-10 Inspecting flywheel and key ...........................20
4 FUEL SYSTEM ...................................................22
4-1 Inspecting air filter ..........................................23
4-2 Inspecting fuel cap and fuel strainer...............23
4-3 Inspecting fuel tank and line...........................24
4-4 Inspecting and replacing tank vent.................25
4-5 Replacing purge bulb .....................................27
4-6 Replacing fuel line and fuel return line ...........28
4-7 Adjusting carburetor .......................................29
4-7-1 General adjusting rules ..................................29
4-7-2 Presetting idle adjust screw, L mixture
needle and H mixture needle .........................29
4-7-3 Adjusting carburetor .......................................31
4-8 Winter plug .....................................................32
4-9 Testing carburetor...........................................33
4-10 Inspecting crankcase pulse passage .............34
4-11 Inspecting metering lever height ....................34
4-12 Inspecting inlet needle valve ..........................35
4-13 Inspecting diaphragm.....................................36
4-14 Replacing Welch plug.....................................36
4-15 Installing carburetor........................................37
5 CLUTCH SYSTEM..............................................38
5-1 Inspecting clutch parts....................................39
5-2 Replacing clutch parts....................................40
5-3 Installing clutch assembly...............................40
6 CHAIN BRAKE SYSTEM....................................42
6-1 Disassembling chain brake ............................43
6-2 Assembling brake parts..................................44
7 SAW CHAIN LUBRICATION SYSTEM...............45
7-1 Inspecting oil cap and strainer........................45
7-2 Inspecting oil tank vent...................................46
7-3 Inspecting oil line............................................47
7-4 Replacing oil line and grommet......................48
7-5 Replacing auto-oiler assembly .......................49
8 ENGINE...............................................................51
8-1 Testing cylinder compression .........................52
8-2 Cleaning cooling air passages .......................52
8-3 Inspecting muffler and exhaust port ...............53
8-4 Testing crankcase and cylinder seal...............54
8-5 Removing engine block..................................55
8-6 Inspecting cylinder..........................................56
8-7 Inspecting piston and piston ring....................57
8-8 Inspecting crankcase and crankshaft.............57
8-9 Replacing oil seal and ball bearing.................58
8-10 Installing piston and piston ring......................59
8-11 Assembling piston into cylinder......................60
8-12 Installing engine block....................................61
9 REAR HANDLE AND CONTROL SYSTEM .......62
9-1 Replacing throttle trigger ................................62
9-2 Replacing cushions ........................................64
10 GUIDE BAR MOUNTING SYSTEM..................65
10-1 Replacing chain tensioner..............................66
10-2 Replacing guide bar stud................................67
11 MAINTENANCE GUIDE....................................68
11-1 Troubleshooting guide....................................68
11-2 Disassembly Chart .........................................70
11-3 Service Intervals.............................................71
INDEX......................................................................72

SERVICE INFORMATION CS-310
2
Cutting devices
Guide bar Part No. 12A0CD3745 14A0CD3752 16A0CD3757
Called length in 12 14 16
Gauge in 0.050
Saw chain Type OREGON 91VG / 91P
Number of drive links 45 52 57
Pitch in 3/8
Gauge in 0.050
1 SERVICE INFORMATION
1-1 Specifications
Model CS-310
Dimensions Length* mm(in) 396 (15.59)
Width mm(in) 232 (9.13)
Height mm(in) 268 (10.55)
Dry weight* kg(lb) 4.0 (8.8)
Engine Type KIORITZ, air-cooled, two-stroke, single cylinder
Rotation Clockwise as viewed from the output end
Displacement cm3(in3) 30.5 (1.861)
Bore mm(in) 36.0 (1.417)
Stroke mm(in) 30.0 (1.181)
Compression ratio 6.7
Carburetor Type Diaphragm horizontal-draft with auto-return choke
Model Walbro WT-946
Venturi size-Throttle bore mm(in) 11.11 - 14.3 (0.437 - 0.562)
Ignition Type CDI (Capacitor discharge ignition) system
Digital magneto
Spark plug BPM8Y
Starter Type Automatic rewind
Rope diameter x length mm(in) 3.0 x 920 (0.12 x 36.2)
Fuel Type Premixed two-stroke fuel
Mixture ratio 50 : 1 (2 %)
Gasoline Minimum 89 octane gasoline
Two-stroke air cooled engine oilISO-L-EGD (ISO/CD13738), JASO M345-FC/FD
Tank capacity L (U.S.fl.oz.) 0.25 (8.5)
Exhaust Muffler type Spark arrestor muffler with catalyst
Clutch Type Centrifugal, 3-shoe slide with 3-tension spring
Guide bar / Saw chain lubrication type Pencil type Automatic oil pump
Oil Tank capacity L (U.S.fl.oz.) 0.26 (8.8)
Sprocket Type Spur
Number of teeth 6
Pitch in 3/8
* Without guide bar and saw chain.

SERVICE INFORMATION
CS-310 3
1-2 Technical data
Engine
Idling speed rpm 3,200 +/- 400
Wide open throttle speed* rpm 12,000 - 13,000
Clutch engagement speed rpm 4,000 - 4,500
Compression pressure MPa (kgf/cm2) (psi) 0.88 (9.0) (128)
Ignition system
Spark plug gap mm(in) 0.6 - 0.7 (0.024 - 0.028)
Minimum secondary voltage at 1500 rpm kV 15.0
Primary coil resistance Ω140 - 180
Secondary coil resistance kΩ1.9 - 2.3
Pole shoe air gaps mm(in) 0.3 - 0.4 (0.012 - 0.016)
Ignition timing at 1,000 rpm °BTDC 14
at 3,000 rpm °BTDC 12
at 8,000 rpm °BTDC 33
at 10,000 rpm °BTDC 35
at 12,000 rpm °BTDC 33
PET-9000 Parameter #1 321
#2 06
Carburetor
Idle adjust screw initial setting turns in** 7/8
L mixture needle initial setting turns back 2 1/2
H mixture needle initial setting turns back 2 1/4
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 rpm Fixed 7 mL/min
mL/min(U.S.fl.oz./min)
BTDC: Before top dead center.
* With 14 in. guide bar and properly adjusted saw chain.
**Set idle adjust screw to the point that its tip contacts throttle plate before initial setting.

SERVICE INFORMATION CS-310
4
1-3 Torque limits
Descriptions Size kgf•cm N•m in•lbf
Starter Starter pawl M 5* 30 - 45 3 - 4.5 26 - 40
system Starter case M 5** 35 - 50 3.5 - 5 30 - 45
Ignition Magneto rotor (Flywheel) M 8 250 - 290 25 - 29 220 - 255
system Ignition coil M 5* 30 - 45 3 - 4.5 26 - 40
Ignition switch M10 15 - 30 1.5 - 3 13 - 26
Spark plug M 14 130 - 170 13 - 17 110 - 150
Fuel Carburetor M 5** 35 - 50 3.5 - 5 30 - 45
system
M 5** 30 - 45 3 - 4.5 26 - 40
Clutch Clutch hub LM 10 230 - 260 23 - 26 200 - 230
Engine Crankcase M 5* 60 - 80 6 - 8 60 - 70
Engine mount M 5** 70 - 110 7 - 11 60 - 95
Muffler M 5 70 - 90 7 - 9 60 - 80
Intake insulator M 5 50 - 70 5 - 7 45 - 60
Others Front handle M 5** 30 - 50 3 - 5 26 - 45
Rear handle assembly M 5** 30 - 50 3 - 5 26 - 45
Brake lever M 4 25 - 35 2.5 - 3.5 22 - 30
Sprocket guard M 4** 10 - 20 1 - 2 9 - 17
Guide bar M 8 200 - 230 20 - 23 175 - 200
Regular bolt, nut and screw M 3 6 - 10 0.6 - 1 5 - 9
M 4 15 - 25 1.5 - 2.5 13 - 22
M 5 25 - 45 2.5 - 4.5 22 - 40
M 6 45 - 75 4.5 - 7.5 40 - 65
LM: Left-hand thread *Apply special repairing materials ** Tapping screw
Material Location Remarks
Adhesive Ball bearing outer / crankcase Loctite #675 or equivalent
Stud bolt
Liquid gasket Crankcase seams ThreeBond 1207D
Thread locking sealant Starter pawl Loctite #242, ThreeBond #1324 or equivalent
Engine mount
Ignition coil Loctite #222, ThreeBond #1342 or equivalent
Grease Clutch needle bearing Lithium based grease
Starter center shaft
Chain brake (metal contact part) Molybdenum grease (approx.1 gram)
1-4 Special repairing materials

SERVICE INFORMATION
CS-310 5
1-5 Service Limits
5K177 5K083 5K084 5K081
5K082 5K016 5K025
5K174 5K181 5K097
5K178
5K173 5K191
ABCD
FGH
KLMP
N
E
Description mm (in)
A Cylinder bore When plating is worn and aluminum can be seen
BPiston outer diameter Min. 35. 91 (1.414)
CPiston pin bore Max. 8. 035 (0.3163)
DPiston ring groove Max. 0. 6 (0.024)
EPiston ring side clearance Max. 0. 1 (0.004)
FPiston pin outer diameter Min. 7. 98 (0.3142)
GPiston ring width Min. 1. 45 (0.057)
HPiston ring end gap Max. 0. 5 (0.02)
KCon-rod small end bore Max. 12. 000 (0.4724)
LCrankshaft runout Max. 0. 01 (0.001)
MSprocket bore Max. 10. 80 (0.4252)
NClutch drum bore Max. 61. 5 (2.42)
PSprocket wear limit Max. 0. 5 (0.02)

SERVICE INFORMATION CS-310
6
1.35
0.4
1.65
1.5
Ignition Air Gap Gauge
#.014 = .35mm
P/N 91004
0
0.4
50
0.8
1.2
1.
MPa
0
OPPAMA
PET-9000
INTEGRATED IGNITION ANALYZER
b
1207D
1-6 Special tools
134
2
58
910 1211
13
7
6
1716 18
14, 15
Key Part Number Description Reference
1 990511-30017 Tachometer PET-1000 Measuring engine speed
2 X605-000050 Torx L wrench Removing and installing bolt
3 897501-03938 Puller Removing magneto rotor
4 897505-16133 Clutch tool Removing and assembling clutch assembly
5 91037 Compression gauge Measuring cylinder compression
6 897702-30131 Piston pin tool Removing and installing piston pin
7 897701-06030 Bearing wedge Removing and crankshaft ball bearings
8 897563-19830 Metering lever gauge Measuring metering lever height on carburetor
9 X686-000000 ThreeBond 1207D Applying crankcase seam
10 900300 Ignition Analyzer: PET-9000 Measuring Ignition timing, Primary/Secondary voltage
11 897726-21430 Oil seal tool Installing oil seals and clutch plate
12 897800-79931 Spark tester Checking ignition system
13 897803-30133 Pressure tester Testing carburettor and crankcase leakage
14 89801 Limiter cap removal tool Removal limiter cap (Left hand thread 2.5 mm)
15 89802 Limiter cap removal tool Removal limiter cap (Left hand thread 3.0 mm)
16 500-500 Welch plug tool Removing and installing welch plug tool
17 Y089-000130 Auto-oiler tool Uninstalling pencil type Auto-oiler
18 X646-000030 Auto-oiler tool Installing pencil type Auto-oiler
19 91004 Module air gap gauge Adjusting pole shoe air gaps
19

STARTER SYSTEM
CS-310 7
Working principle
1. When starter grip (J) is pulled, rope reel (D)
rotates.
2. The rotation force of rope reel (D) is transmitted
to pawl catcher (F) by power spring (E).
3. Pawl catcher (F) engages with starter pawls on
flywheel to turn crankshaft.
4. The load from compression pressure in cylinder
will keep crankshaft from rotating as power spring
(E) is twisted and accumulates energy.
5. As starter grip is pulled further, more energy is
stored in power spring (E) until accumulated energy
is enough to overcome compression pressure in
cylinder.
6. When accumulated energy in power spring (E)
overcomes the load from compression pressure in
cylinder, crankshaft is rotated.
7. Power spring absorbs compression resistance of
cylinder and snatch back of engine during starting
action.
8. When starter rope is released, rope reel (D) is
returned together with power spring (E) and pawl
catcher (F) by rewind spring tension.
9. After engine starts, starter pawls pivot outward by
centrifugal force and disengage from pawl catcher
(F).
2 STARTER SYSTEM (i-30 starter)
(A) Starter case
(B) Rewind spring
(C) Rewind spring case assembly
(D) Rope reel
(E) Power spring
(F) Pawl catcher
(G) Screw
(H) Starter rope
(J) Starter grip
Construction
1. Rewind spring case assembly (C) is installed
inside starter case (A).
2. Rope reel (D) with starter rope (H) is installed
on rewind spring case assembly.
3. Hook located on the backside of rope reel
engages with end (b) of rewind spring (B).
4. Power spring (E) is installed on rope reel.
5. Hook of power spring engages with rope reel
and top end hook (e) of power spring engages
with pawl catcher (F).
(E)
(D)
(A)
(C)
(b)
(e)
(B)
(H)
(F)
(G)
(J)

STARTER SYSTEM CS-310
8
2-1 Disassembling starter assembly
1. Remove sprocket guard (A).
2. Remove brake lever (B) and cylinder cover (C).
3. Remove three screws and remove starter as-
sembly (D) from unit.
4. Pull out starter rope about 30 cm (12 in) and
hold rope reel (E) by hand. Loop excess rope in
rope reel notch (e) as shown.
5. Rotate rope reel (E) counterclockwise to release
tension of rewind spring.
6. Remove screw (F).
7. Remove pawl catcher (G) and power spring (H).
8. Remove rope reel (J) from starter case (K) slow-
ly to prevent rewind spring (L) from unwinding.
9. Remove rewind spring case assembly (M) from
starter case (K).
WARNING DANGER
Wear eye protection and take care when
removing starter drum. Rewind spring may
unwind suddenly and cause personal injury.
A
B
C
D
F
G
H
e
E
JK
L
M

STARTER SYSTEM
CS-310 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.
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 start-
er case, then pass starter rope through starter grip
and make a knot as shown.
6. Tighten knot. Push knot into recess of starter
grip.
4K287
A
B
C
DD

STARTER SYSTEM CS-310
10
2-3 Assembling starter
1. If rewind spring (A) is unwound from rewind
spring case (B), wind the spring inside case as
shown.
2. Carefully install rewind spring case assembly
(C) on starter case, matching hole (c) with post (D).
Hook (a) of rewind spring should contact with post
(E) of starter case.
3. Assemble rope reel (F) engaging hook (f1) with
hook (a) of rewind spring.
4. Check for proper engagement of rewind spring
and rope reel by turning rope reel (F) clockwise
and counterclockwise.
A
B
E
D
c
C
F
f1
a
a
F

STARTER SYSTEM
CS-310 11
5. Install power spring (G), engaging hook (g1)
with rope reel groove (f2).
6. Install pawl catcher (H), engaging hole (h) with
power spring top end hook (g2).
7. Reinstall screw (J) on starter post.
8. Pull out starter rope inside starter case. Rotate
rope reel clockwise several turns with starter rope
hooked at notch (f3) as shown. Hold rope reel to
prevent it from unwinding and pull out starter grip
to take the rope slack.
9. 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 (8).
10. 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.
11. If rope reel can not be turned clockwise, reduce
tension by rotating rope reel counterclockwise one
turn with starter rope hooked at notch (f3).
2-3 Assembling starter (continued)
H
G
g1
f2
h
g2
J
f3

STARTER SYSTEM CS-310
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 piston
stopper 897537-30130 (E) in spark plug hole to
stop crankshaft rotation 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
G
B
F
F
E

IGNITION SYSTEM
CS-310 13
(A) Flywheel (E) Spark plug cap
(B) Ignition coil (F) Switch lead
(C) Spark plug (G) Ground lead
(D) Spark plug cap coil (H) Ignition switch
3 IGNITION SYSTEM
(A)
(B)
(C)
(D)
(E)
(G)
(H)
(F)

IGNITION SYSTEM CS-310
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-310 15
3-2 Testing spark
1. Remove cylinder cover. Remove spark plug cap
from spark plug.
2. Connect spark plug cap to spark tester
990511-30023 (A), and connect spark tester lead
(B) on spark plug as shown.
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 upward (“ON” position). Pull
starter grip several times.
5. If spark is steady blue or white at the tester gap,
ignition system is considered good.
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 fouling,
cracked or broken insulator, cracked outer elec-
trode, or rounded center electrode. Clean or
replace spark plug as required.
2. Set spark plug gap (A) by bending outer elec-
trode (B).
Standard : 0.6 to 0.7 mm (0.024 to 0.028 in)
NOTE: Take care not to crack outer electrode
when bending.
3. 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.
A
B
a2
GASO
LINELINE
B
a1
A
a2

IGNITION SYSTEM CS-310
16
3-4 Inspecting ignition switch
1. Remove 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 upward (“ON” position),
tester should indicate infinite resistance.
5. When ignition switch is in “STOP” position, tes-
ter should show that the circuit is in conducting
state (closed circuit).
6. If ignition switch is defective, replace with a new
one.
B
A
A

IGNITION SYSTEM
CS-310 17
3-5 Replacing ignition switch
1. Remove cylinder cover.
2. Push down air filter retainer (A) and remove air
filter (B).
3. Loosen nut (C), and remove ignition switch (D)
and ground lead (E) from the unit. Remove switch
lead (F) from ignition switch.
4. Assemble switch lead (F) to new ignition switch.
5. Assemble ground lead (E) and new ignition
switch on the unit, aligning notch (d) of ignition
switch with tab (G) of the unit. Fasten nut (C) on
ignition switch.
A
B
F
D
E
F
E
G
C
C
d

IGNITION SYSTEM CS-310
18
3-6 Inspecting ignition coil resistance
1. Remove 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 1.9 to 2.3
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. Keep probe (C) on cylinder fin (B). Remove
probe (D) from spark plug cap coil (A) and connect
it to ignition coil core to confirm that the circuit is in
conducting state (closed circuit). If the circuit is not
in conducting state, ensure conduction between
ignition coil bolt and cylinder.
6. If the reading at step 3 or 4 is not in the range of
1.9 to 2.3 kΩ, replace with a new ignition coil (Go
to “3-8 Replacing ignition coil”).
A
B
D
C