Stihl MS 210 User manual

STIH)
STIHL MS 210, 230, 250 2003-04

1MS 210, MS 230, MS 250
q
© ANDREAS STIHL AG & Co. KG, 2007
Contents
1. Introduction 2
2. Safety Precautions 3
3. Specifications 4
3.1 Engine 4
3.1.1 Engine (USA only) 4
3.2 Fuel System 5
3.3 Ignition System 5
3.4 Chain Lubrication 5
3.5 Tightening Torques 6
4. Troubleshooting
Chart 8
4.1 Clutch, Chain Drive,
Chain Brake,
Chain Tensioner 8
4.2 Rewind Starter 9
4.3 Chain Lubrication 10
4.4 Ignition System 11
4.5 Carburetor 12
4.6 Engine 14
5. Clutch, Chain Drive,
Chain Brake and
Chain Tensioner 15
5.1 Clutch Drum / Chain
Sprocket 15
5.2 Chain Catcher 16
5.3 Clutch 16
5.4 Chain Brake 18
5.4.1 Checking Operation 18
5.4.2 Removing 19
5.4.3 Installing 20
5.5 Front Chain Tensioner 22
5.6 Side Chain Tensioner 22
6. Engine 23
6.1 Muffler/Spark
Arresting Screen 23
6.2 Leakage Test 24
6.2.1 Preparations 24
6.2.2 Pressure Test 25
6.2.3 Vacuum Test 26
6.3 Oil Seals 26
6.4 Removing and
Installing 28
6.5 Cylinder 29
6.6 Piston 31
6.7 Piston Rings 33
6.8 Crankshaft 33
6.9 Decompression Valve 34
7. Ignition System 34
7.1 Spark Plug Boot 35
7.2 Ignition Module 35
7.3 Testing the
Ignition Coil 36
7.4 Checking the
Wiring Harness 36
7.4.1 Ignition Timing 37
7.4.2 Removing and
Installing 37
7.5 Flywheel 38
7.6 Ignition System
Troubleshooting 39
8. Rewind Starter 42
8.1 General 42
8.2 Removing and
Installing 42
8.3 Rope Rotor 42
8.4 Segment 44
8.5 Starter Rope 44
8.5.1 Elastostart 45
8.5.2 Tensioning 46
8.6 Rewind Spring 47
8.7 Pawl 48
9. AV Handle System/
Handle Housing 48
9.1 Annular Buffers 48
9.2 Front Handle 49
9.3 Handle Housing 50
9.4 Switch Shaft 52
9.5 Contact Spring 52
9.6 Throttle Trigger/
Interlock Lever 53
10. Chain Lubrication 54
10.1 Pickup Body 54
10.2 Connector/
Suction Hose 55
10.3 Valve 55
10.4 Worm 56
10.5 Oil Pump 57
11. Fuel System 58
11.1 Air Filter 58
11.2 Carburetor 59
11.2.1 Leakage Test 59
11.2.2 Removing and
Installing 60
11.2.3 Adjusting
(Carburetor
without Limiter Cap) 61
11.2.4 Adjusting
(Carburetor with
Limiter Cap) 62
11.2.5 Standard Setting
(Carburetor with
Limiter Cap) 62
11.3 Tank Vent 63
11.4 Pickup Body 64
11.5 Suction Hose 64
11.6 Manual Fuel Pump 65
11.7 Hoses 65
11.8 Fuel Tank 67
12. Special Servicing
Tools 69
13. Servicing Aids 71

2MS 210, MS 230, MS 250
This service manual contains
detailed descriptions of all the repair
and servicing procedures specific to
this power tool series.
As the design concept of model
MS 210, 230 and 250 chainsaws is
almost identical, the descriptions
and servicing procedures in thus
manual generally apply to all three
models. Differences are described
in detail.
You should make use of the
illustrated parts lists while carrying
out repair work. They show the
installed positions of the individual
components and assemblies.
Refer to the latest edition of the
relevant parts list to check the part
numbers of any replacement parts.
A fault on the machine may have
several causes. To help locate the
fault, consult the troubleshooting
charts for all assemblies and
systems in this manual and the
"STIHL Service Training System".
Refer to the "Technical Information”
bulletins for engineering changes
which have been introduced since
publication of this service manual.
Technical information bulletins also
supplement the parts list until a
revised edition is issued.
The special tools mentioned in the
descriptions are listed in chapter
"Special Servicing Tools" of this
manual. Use the part numbers to
identify the tools in the "STIHL
Special Tools" manual.
The manual lists all special
servicing tools currently available
from STIHL.
Symbols are included in the text and
pictures for greater clarity.
The meanings are as follows:
In the descriptions:
:= Action to be taken as
shown in the illustration
(above the text)
– = Action to be taken that is
not shown in the illustration
(above the text)
In the illustrations:
APointer (short)
aDirection of movement (long)
b4.2 = Reference to another
chapter, i.e. chapter 4.2
in this example.
Service manuals and all technical
Information bulletins are intended
exclusively for the use of STIHL
servicing dealers. They must not be
passed to third parties.
Servicing and repairs are made
considerably easier if the clamp (1)
5910 890 2000 is used to mount the
machine on assembly stand (2)
5910 890 3100 so that one clamp
screw engages the outer 10 mm
bore (3) in the assembly stand.
To service the underside of the
machine (e.g. remove the oil pump),
turn the machine through
180 degrees and mount it so that
one clamp screw engages the inner
10 mm bore (1) in the assembly
stand.
Note:
Pull the hand guard back against
the front handle for this purpose.
Always use original STIHL
replacement parts.
They can be identified by the
STIHL part number,
the STIH) logo
and the STIHL parts symbol (
This symbol may appear alone on
small parts.
1. Introduction

3MS 210, MS 230, MS 250
If the engine is started up in the
course of repairs or maintenance
work, observe all local and country-
specific safety regulations as well
as the safety precautions and
warnings in the owner’s manual.
Gasoline is an extremely flammable
fuel and can be explosive in certain
conditions.
Improper handling may result in
burns or other serious injuries.
Warning!
Do not smoke or bring any fire,
flame or other source of heat near
the fuel. All work with fuel must be
performed outdoors only. Spilled
fuel must be wiped away
immediately.
2. Safety Precautions

4MS 210, MS 230, MS 250
3. Specifications
3.1 Engine
MS 210 MS 230 MS 250
Displacement: 35.2 cm340.2 cm345.4 cm3
Bore: 40 mm 40 mm 42.5 mm
Stroke: 28 mm 32 mm 32 mm
Engine power to ISO 7293: 1.6 kW (2.2 HP)
at 9,000 rpm
2.0 kW (2.7 HP)
at 10,000 rpm
2.3 kW (3.1 HP)
at 10,000 rpm
Max. permissible engine speed
(with bar and chain): 12,500 rpm 14,000 rpm 14,000 rpm
Idle speed: 2,800 rpm
Clutch: Centrifugal clutch without linings
Clutch engages at: 4,100 rpm
Crankcase leakage test
at gauge pressure: 0.5 bar
under vacuum: 0.5 bar
3.1.1 Engine (USA only)
MS 210 MS 230 MS 250
Displacement: 2.15 cu. in 2.45 cu. in 2.77 cu. in
Bore: 1.57 in 1.57 in 1.67 in
Stroke: 1.10 in 1.26 in 1.26 in
Engine power to ISO 7293: 1.5 kW (2.01 HP) 1.9 kW (2.55 HP) 2.2 kW (2.95 HP)
Max. permissible engine speed
(with bar and chain): 12,500 rpm 14,000 rpm 14,000 rpm
Idle speed: 2,800 rpm
Clutch: Centrifugal clutch without linings
Clutch engages at: 4,100 rpm
Crankcase leakage test
at gauge pressure: 7.25 psi
under vacuum: 7.25 psi

5MS 210, MS 230, MS 250
3.2 Fuel System
Carburetor leakage test
at gauge pressure: 0.8 bar (11.6 psi)
Function of tank vent
at gauge pressure: 0.3 bar (4.35 psi)
0.05 bar (0.72 psi)
Fuel: see owner’s manual
3.3 Ignition System
Air gap between ignition module
and fanwheel: 0.2 – 0.4 mm (0.008 – 0.015 in)
Spark plug (resistor type): Bosch WSR 6F
NGK BPMR 7A
Electrode gap: 0.5 mm (0.02 in)
3.4 Chain Lubrication
Fully automatic speed-controlled oil pump with rotary piston
Oil delivery rate: approx. 7.5 cc/min (0.46 cu in/min) at 10,000 rpm

6MS 210, MS 230, MS 250
3.5 Tightening Torques
DG screws are used in the polymer and light-alloy components. These screws form a permanent thread when
they are installed for the first time. They can be removed and installed as often as necessary without
detrimentally affecting the strength of the screwed assembly, providing the specified tightening torque is
observed. For this reason always use a torque wrench.
Fastener Thread
size
For component Torque Remarks
kpm Nm
Spline screw IS-M4x15 Cain brake cover 0.2 2.0
Spline screw IS-D4x15 Handle molding 0.16 1.6
Spline screw IS-P5x16 Connector (engine housing/oil pump) 0.4 4.0
Spline screw IS-M4x15 Ground wire (to cylinder) 0.35 3.5
Spline screw IS-DG5x24 Handle housing/front handle 0.35 3.5
Spline screw IS-DG5x24 Hand guard 0.35 3.5
Spline screw IS-DG5x24 Fan housing 0.35 3.5
Spline screw IS-DG5x24 Buffer (to front handle) 0.35 3.5
Spline screw IS-DG5x24 Buffer (to engine housing) 0.35 3.5
Spline screw IS-DG5x24 Ignition module (to engine housing) 0.4 4
Spline screw IS-DG5x24 Cylinder (to engine housing) 0.95 9.5
Collar screw DG 8x18 Guide bar mounting 1.6 16
M12x1 Carrier (clutch) 5.0 50
M14x1.25 Spark plug 2.5 25
Collar locknut M5 Muffler 0.8 8
Collar locknut M5 Filter housing/carburetor 0.27 2.7
Collar nut M8x1 Flywheel to crankshaft 2.8 28
M12x1.5 Decompression valve 1.4 14
Spline screw IS-DG5x16 Spiked bumper 0.37 3.7

7MS 210, MS 230, MS 250
Use the following procedure to fit a DG screw in an existing thread:
– Place the DG screw in the hole and rotate it counterclockwise until drops down slightly.
– Tighten the screw clockwise to the specified torque.
This procedure ensures that the screw engages properly in the existing thread and does not form a new thread,
which would weaken the assembly.
Note:
Power screwdriver speed setting for polymer:
– DG screws max. 500 rpm

8MS 210, MS 230, MS 250
4. Troubleshooting Chart
4.1 Clutch, Chain Drive, Chain Brake, Chain Tensioner
Condition Cause Remedy
Saw chain stops under load at full
throttle
Clutch shoes badly worn Install new clutch
Clutch drum badly worn Install new clutch drum
Brake band stuck Check freedom of movement and
function of brake band
Saw chain rotates at idle speed Engine idle speed too high Readjust with idle speed screw
(counterclockwise)
Clutch springs stretched or fatigued Replace the clutch springs
Clutch spring hooks broken Replace the clutch springs
Loud noises Clutch springs stretched or fatigued Replace all clutch springs
Needle cage damaged Fit new needle cage
Clutch shoe retainer broken Fit new retainer
Clutch shoes and carrier worn Install new clutch
Chain sprocket wears rapidly Chain not properly tensioned Tension chain as specified
Wrong chain pitch Fit chain of correct pitch
Saw chain does not stop
immediately when brake is
activated
Brake spring stretched or broken Fit new brake spring
Brake band stretched / worn /
broken
Fit new brake band

9MS 210, MS 230, MS 250
4.2 Rewind Starter
Condition Cause Remedy
Starter rope broken Rope pulled out too vigorously as
far as stop or over edge, i.e. not
vertically
Fit new starter rope
Normal wear Fit new starter rope
Rewind spring broken
(rope does not rewind)
Spring overtensioned – no reserve
when rope is fully extended
Fit new rewind spring
Very dirty or corroded Clean or replace rewind spring
Starter rope can be pulled out
almost without resistance
(crankshaft does not turn)
Guide peg on pawl or pawl itself is
worn
Fit new pawl
Spring clip fatigued Fit new spring clip
Starter rope is difficult to pull
and rewinds very slowly
Starter mechanism is very dirty
(dusty conditions)
Thoroughly clean complete starter
mechanism
Lubricating oil on rewind spring
becomes viscous at very low
outside temperatures (spring
windings stick together)
Apply a few drops of kerosine
(paraffin) to spring, then pull rope
carefully several times until normal
action is restored

10 MS 210, MS 230, MS 250
4.3 Chain Lubrication
Important!
In the event of trouble with the chain
lubrication system, always
investigate the other possible
sources of faults before
disassembling the oil pump.
Condition Cause Remedy
Chain receives no oil Oil tank empty Fill up with oil
Oil inlet hole in guide bar is
blocked
Clean oil inlet hole
Intake hose or pickup body
(strainer) clogged or intake hose
ruptured
Wash intake hose and pickup body
(strainer) in fresh STIHL cleaner or
replace if necessary
Valve in oil tank blocked Clean or replace valve
Oil pump damaged or worn Install new oil pump
Machine losing chain oil Oil seal leaking Replace oil seal
Bore in pump housing worn Install new oil pump
Oil pump delivers too little oil Oil pump worn Install new oil pump

11MS 210, MS 230, MS 250
4.4 Ignition System
Warning!
Exercise extreme caution while
carrying out maintenance and
repair work on the ignition system.
The high voltages which occur can
cause serious or fatal accidents!
Condition Cause Remedy
Engine runs roughly, misfires,
temporary loss of power
Spark plug boot is loose Press boot firmly onto spark plug
and fit new spring if necessary
Spark plug sooted, smeared
with oil
Clean the spark plug or replace if
necessary
Weak spark or no spark Faulty insulation on ignition lead or
short circuit wire. Use ohmmeter to
check ignition lead for break. If
break is detected or high resistance
measured, fit a new ignition lead
Incorrect air gap between ignition
coil and flywheel
Set air gap correctly
Flywheel cracked or has other
damage
Install new flywheel
Crankcase damaged (cracks) Install new crankcase
No ignition spark Check operation of Master Control
lever, ignition module and ignition
lead

12 MS 210, MS 230, MS 250
4.5 Carburetor
Condition Cause Remedy
Carburetor floods;
engine stalls
Inlet needle not sealing. Foreign
matter in valve seat or cone
damaged
Remove and clean or replace the
inlet needle, clean the fuel tank,
pickup body and fuel line if
necessary
Inlet control lever sticking on
spindle
Free off inlet control lever
Helical spring not located on nipple
of inlet control lever
Remove the inlet control lever and
refit it correctly
Perforated disc on diaphragm is
deformed and presses constantly
against the inlet control lever
Fit a new metering diaphragm
Inlet control lever too high
(relative to design position)
Set inlet control lever flush with top
edge of housing or bottom of
metering chamber
Poor acceleration Idle jet too lean Back off low speed screw (L)
slightly
Main jet too lean Back off high speed screw (H)
slightly
Inlet control lever too low
(relative to design position)
Set inlet control lever flush with top
edge of housing or metering
chamber face
Inlet needle sticking to valve seat Remove inlet needle, clean and
refit
Connecting bore to atmosphere
blocked
Clean bore
Diaphragm gasket leaking Fit a new diaphragm gasket
Metering diaphragm damaged or
shrunk
Fit a new metering diaphragm

13MS 210, MS 230, MS 250
Condition Cause Remedy
Engine will not idle,
idle speed too high
Throttle shutter opened too wide by
idle speed screw (LA)
Reset idle speed screw (LA)
correctly
Engine leaking Seal the engine
Engine stalls at idle speed Idle jet bores or ports blocked Clean jet bores and ports with
compressed air
Idle jet too rich Screw down low speed screw (L)
slightly
Setting of idle speed (LA)
incorrect – throttle shutter
completely closed
Set idle speed screw (LA) correctly
Small plastic plate in valve jet
does not close
Clean or renew valve jet
Engine speed drops quickly under
load – low power
Air filter plugged Clean or renew the air filter
Tank vent faulty Clean tank vent or replace if
necessary
Leak in fuel line between tank and
fuel pump
Seal connections or install new fuel
line
Pump diaphragm damaged or
fatigued
Fit a new pump diaphragm
Main jet bores or ports blocked Clean the bores and ports
Fuel pickup body dirty Clean the pickup body, fit a new
filter
Fuel strainers dirty Clean the fuel strainers

14 MS 210, MS 230, MS 250
4.6 Engine
Always check and, if necessary,
repair the following parts before
looking for faults on the engine:
– Air filter
– Fuel system
– Carburetor
– Ignition system
Condition Cause Remedy
Engine does not start easily, stalls
at idle speed, but operates normally
at full throttle
Oil seals in crankcase damaged Replace the oil seals
Gasket on carburetor spacer flange
leaking
Fit a new gasket
Engine pan leaking Seal the engine pan
Crankcase damaged (cracks) Replace the crankcase
Muffler leaking Seal or replace the muffler
Engine does not deliver full power
or runs erratically
Secondary air seepage through
leaking gaskets on carburetor
spacer flange
Fit new gaskets
Piston rings worn or broken Fit new piston rings
Muffler / spark arresting screen
carbonized
Clean the muffler (inlet and
exhaust), replace spark arresting
screen
Air filter element dirty Replace air filter element
Fuel / impulse line severely kinked
or damaged
Replace lines or position them free
from kinks
Decompression valve sticking Replace the decompression valve
Engine overheating Insufficient cylinder cooling. Air
inlets in fan housing blocked or
cooling fins on cylinder very dirty
Thoroughly clean all cooling air
openings and the cylinder fins

15MS 210, MS 230, MS 250
– Remove the chain sprocket
cover.
:Disengage the chain brake by
pulling the hand guard toward the
front handle.
VA
143RA004
:Remove the E-clip (1).
:Remove the washer (2).
– Remove the rim sprocket, if fitted.
:Pull off the clutch drum / chain
sprocket.
:Take the needle cage out of the
sprocket.
– Clean and inspect the clutch
drum / chain sprocket.
VA
143RA007
:Inspect the clutch drum (1) for
signs of wear.
If there are noticeable wear marks
on the inside diameter of the clutch
drum, check its wall thickness. If it is
less than 80% of the original wall
thickness, fit a new clutch drum.
VA
148RA101
80%
100%
1
!
If the clutch drum has to be
replaced, also check the brake band
– b5.4.
:If the clutch drum/chain sprocket
is still serviceable, use No. 120
emery paper or emery cloth
(grain size approx. 120 µm) to
clean and roughen its friction
surface.
Reassemble in the reverse
VA
176RA330
sequence.
– Clean stub of crankshaft. Wash
needle cage in clean white spirit
and lubricate with grease –
b13.
– Replace damaged needle cage.
– Rotate clutch drum/chain
sprocket and apply slight
pressure at the same time until oil
pump drive spring engages
properly.
– If rim sprocket was fitted, re-
install it with the cavities facing
outward.
5. Clutch, Chain Drive,
Chain Brake and Chain
Tensioner
5.1 Clutch Drum / Chain
Sprocket

16 MS 210, MS 230, MS 250
:Sprocket cover with integrally
molded chain catcher.
If the chain catcher has broken off,
repair as follows:
VA
208RA001
:Remove the chain bumper
strip (1).
:Pry the plug (2) out of the front
right-hand AV element.
VA
2
08RA000
2
1
:Oil the cylindrical part (1) of the
replacement chain catcher.
:Push the chain catcher into the
AV element (2) and engage the
peg (3) in the housing bore (4) at
the same time.
VA
208RA003
1
4
3
2
– Fit the chain bumper strip.
Assemble all other parts in the
reverse sequence.
Troubleshooting chart – b4.1.
– Remove the clutch drum/chain
sprocket – b5.1.
– Remove the air filter – b11.1.
:Take out the shutter.
– Pull boot off the spark plug.
– Unscrew the spark plug.
– Close the decompression valve,
if fitted.
:Push the locking strip (1)
0000 893 5903 into the cylinder.
VA
135RA022
1
5.2 Chain Catcher 5.3 Clutch

17MS 210, MS 230, MS 250
:Unscrew the clutch from the
crankshaft clockwise (left-hand
thread).
VA
135RA023
Disassembling the clutch:
:Use hook (2) 5910 890 2800 to
remove the clutch springs (1).
– Pull the clutch shoes off the
carrier.
VA
208RA028
21
:Pull the retainers, if fitted, off the
clutch shoes.
VA
208RA031
– Clean all parts with STIHL
cleaner.
– Replace any damaged parts.
VA
208RA026
Assembling the clutch:
:Slip the retainers onto the clutch
shoes.
VA
208RA029
:On retainers with tabs (1), the
narrow side (2) must be next to
the series number (3).
VA
208RA032
3
1 2
:Fit the clutch shoes over the
arms (1) of the clutch carrier so
that the series number (2) is on
the same side as the larger
hexagon (3).
VA
208RA027
2 1 3
:Clamp the clutch in a vise.
VA
208RA030

18 MS 210, MS 230, MS 250
:Attach one end of each spring (1)
to the clutch shoes.
:Use the hook (2) 5910 890 2800
to attach other ends of springs
and press them firmly into the
clutch shoes.
VA
208RA033
1
2
:Screw on the clutch and tighten
down to 50 Nm (37 lbf.ft).
– Install the clutch drum / chain
sprocket – b5.1.
VA
135RA024
– Remove locking strip from the
cylinder.
– Insert spark plug and tighten
down to 25 Nm (18.5 lb.ft).
:If spark plug has a separate
terminal nut, make sure it is
VA
250RA008
properly tightened down.
– Fit boot on the spark plug.
:Fit the shutter so that its lugs
engage the recesses in the
handle housing.
– Install the air filter – b11.1.
The chain brake is one of the most
important safety devices on the
chainsaw. Its efficiency is measured
in terms of the chain braking time,
i.e. the time that elapses between
activating the brake and the saw
chain coming to a complete
standstill. The shorter the braking
time, the better the efficiency and
protection offered against being
injured by the rotating chain.
Contamination (with chain oil, chips,
fine particles of abrasion, etc.) and
smoothing of the friction surfaces of
the brake band and clutch drum
impair the coefficient of friction.
This, in turn, reduces the frictional
forces and thus prolongs the
braking time. A fatigued or stretched
brake spring has the same negative
effect.
– Start the engine.
– With the chain brake activated
(locked), open throttle wide for a
brief period (max. 3 seconds) –
the chain must not rotate.
– With the chain brake released,
open throttle wide and activate
the brake manually – the chain
must come to an abrupt stop.
The braking time is in order if
deceleration of the saw chain is
imperceptible to the eye.
5.4 Chain Brake
5.4.1 Checking Operation

19MS 210, MS 230, MS 250
– Remove the clutch drum / chain
sprocket – b5.1.
– Release brake spring tension by
pushing hand guard forward.
– Remove upper bumper strip from
the tensioner.
:Take out the screws.
– Remove the cover.
VA
135RA026
:Carefully ease the brake spring
off the anchor pin and take it off
the bell crank.
:Pry the brake band out of the
engine housing.
– Disconnect the brake band from
the bell crank.
VA
135RA027
Install a new brake band if:
– there are noticeable signs of
wear (large areas on inside
diameter and/or parts of outside
diameter) and its remaining
thickness is less than 0.6 mm
(0.024").
VA
170RA014
Important!
Thickness of brake band must not
be less at any point.
:If the brake band is still
serviceable, use No. 120 emery
paper or emery cloth (grain size
approx. 120 µm) to clean and
roughen its entire friction surface
(inside diameter).
:Remove the screw (arrow) from
the hand guard.
VA
135RA028
:Remove the E-clip.
VA
135RA029
:Remove strap from bell crank
pivot pin (1).
:Push the strap sideways and lift it
off the hand guard pivot pin (2).
VA
135RA030
2 1
5.4.2 Removing