Technical Information · issue 22 of 2008
New Trimmer STIHL FS 40
IssueTI 22/2008
Full text
Page 1 of 11
STIH)
Technical Information 22.2008
New Trimmer STIHL FS 40 – Series 4144
Contents
1. Technical description
2. Specifications
3. Cutting tools
4. Special Accessories
5. Servicing accessories
6. Spare parts
7. Servicing
The new lightweight FS 40 C-E is an addition to the
curved shaft line of trimmers.
The ergonomically designed controls, together with
the favorable power-to-weight ratio, makes this
machine easy to handle and comfortable to use.
The new FS 40 C-E has a curved shaft and will use
the same mowing head support as the FS 45.
Typical applications are the same as those for the
FS 45.
TI_22_2008_30_01_02.fm englisch / English USA
)m~ge 2 Technical Information 22.2008
1. Technical description 1.4 Engine with stratified scavenging
1.1 Function of stop switch and ignition 1.4.1 Mechanical Design
546TI000 KN
3
When the stop switch (1) is released, it returns to 2 4
the RUN position: The ignition is switched on – the
engine is ready for starting and can be started. If the 1
stop switch is pressed into the 0 position, the
546TI002 KN
ignition is switched off. Once the engine comes to a
complete stop, the ignition automatically resets so
the engine can be started.
Fresh mixture (1) and clean air (2) are fed into
1.2 Choke lever different ports via the carburetor. Integrally molded
control channels (3) on both sides of the piston skirt.
Open and close the connection between the clean
air port and the transfer port (4). No additional
components are required for controling the clean air.
An air cushion (air without fuel) separates the fresh
mixture (fuel-air mixture) and exhaust. The air
cushion is placed in front of the fresh mixture, at the
beginning of the "exhaust and transfer" stroke. The
1 clean air flows from the transfer ports into the
combustion chamber purging the exhaust gases
546TI001 KN
and preventing the incoming fresh mixture from
exiting the exhaust port. This results in reduced
emissions through the reduction of fresh mixture
To start the engine, the choke lever (1) must be
losses and lower fuel consumption.
pressed and rotated to the Cold start g or Warm
start < position. Once the engine has been started
and the interlock lever and throttle trigger have been
engaged, the choke lever automatically returns to
the Run F position. Manual disengagement of the
choke lever will not be required.
1.3 STIHL Easy2Start™
. for reduced cranking effort and lower cranking
speed
. smooth starts
TI_22_2008_30_01_02.fm Page 2 of 11
Technical Information 22.2008 Page 3
1.4.2 Carburetor
2 3
2 6 3 5
546TI003 KN
a) Full load, b) Idle c) Cold start d) Warm start
partial load
Full load and partial load Cold start
The air filter (1) divides the intake air into two During a cold start, the choke shutter is closed.
streams. The choke shutter (2) and throttle The throttle shutter is slightly open. The amount of
shutter (3) are open. The intake air flows above and air necessary for an optimal starting mixture is
below the choke and throttle shutters through the drawn in through the holes in the choke shutter; the
carburetor (4). The fuel is drawn into the top part of necessary amount of fuel is drawn in from the idle
the carburetor and flows through the venturi – where and main jet.
the fresh mixture is formed. Warm start
The spacer flange (5) channels the fresh mixture
into the crankcase and the clean air into the transfer During a warm start, the choke and throttle shutters
ports. are opened to a defined angle so an ideal mixture of
air and fuel is fed to the engine for starting.
The baffle plate (6) in the carburetor, separates the
fresh mix and clean air paths from one another.
Idle
The choke shutter is open. The throttle shutter is
closed so far that only a small gap remains open at
the carburetor housing. A rich mixture is drawn in
through the idle hole located at this gap. Air that
dilutes the rich mixture into an optimal idle mixture is
drawn in through two holes in the throttle shutter and
the annular gap.
TI_22_2008_30_01_02.fm
)m~ge 4 Technical Information 22.2008
1.5 Loop handle 1.6 Cutting radius
546TI014 KN
546TI015 KN
When the loop handle is secured flush against the FS 40 C-E – Deflector with cutting radius R 1
engine housing the recommended minimum
distance (A) between the handles should measure The deflector approved for the FS 40 C-E is
approx. 7.9 in (200 mm). No additional aids are designed for the cutting radius R 1 = 7.5 in
required for setting the minimum distance. The (190 mm).
FS 40 C-E, handle is clamped onto the shaft with a The cutting radius is matched to the engine
screw. performance of the machine.
TI_22_2008_30_01_02.fm Page 3 of 11
Technical Information 22.2008 Page 5
2. Specifications
2.1 Engine
Single cylinder two-stroke engine
Displacement: 1.66 cu. in (27.2 cc)
Bore: 1.34 in (34 mm)
Stroke: 1.18 in (30 mm)
Engine power to ISO 8893: 0.95 bhp (0.7 kW)
Torque: 0.92 lbs.ft (1.25 Nm)
Idle speed: 2800 rpm (1/min)
Clutch engages at: 4200 rpm (1/min)
Cut-off speed
(Nominal value): 10000 rpm (1/min)
Starter mechanism: Dual pawl system
– Starter rope: Diameter 0.106 in, length 35.8 in
– Pull-out reserve: (Diameter 2.7 mm, length 910 mm)
1.25 – 2.25 revolutions
2.2 Fuel system
Carburetor: all-position diaphragm carburetor with integral fuel pump.
Settings
High speed screw H (basic setting)
– without limiter cap for servicing dealers: 1 1/2 turns open
– with limiter cap for users: 3/4 turn counterclockwise (max. to stop)
Low speed screw L
(Standard setting): 3/4 turn counterclockwise
Idle speed screw LA: As required, cutting attachment must not turn
Fuel tank capacity: 11.5 fl.oz (340 cc)
Fuel mixture: See instruction manual
Mix ratio: See instruction manual
2.3 Ignition system
Ignition module: with electronic magneto ignition
Spark plug
(suppressed): NGK CMR 6 H
Electrode gap: 0.020 in (0.5 mm)
TI_22_2008_30_01_02.fm
)m~ge 6 Technical Information 22.2008
2.4 Dimensions
Total length without cutting attachment:
FS 40 C-E: 57.1 in (1450 mm)
2.5 Weight
Without cutting attachment and deflector
FS 40 C-E:
– with Easy2Start™ 9.9 lbs (4.5 kg)
3. Cutting tools
The following cutting attachment are approved.
2
/L
ur n
ch
1 2
ch
nu
r/L
1
4
3
681TI161 KN
1 STIHL AUTOCUT® C 5-2
mowing head 4006 710 2106
2 STIHL AUTOCUT® 5-2
mowing head 4006 710 2103
3 STIHL FixCut™ 5-2
mowing head 4006 710 2118
4 STIHL PolyCut™ 6-3
mowing head 4006 710 2104
TI_22_2008_30_01_02.fm Page 4 of 11
Technical Information 22.2008 Page 7
4. Special Accessories
4.1 General
Part name Part No. Use
Harness 4130 710 9000
4.2 Mowing line for mowing heads
Line diameter / color Use
0.080 in (2.0 mm) / green AUTOCUT® 5-2, AUTOCUT® C 5-2, FixCut™ 5-2
0.095 in (2.4 mm) / orange FixCut™ 5-2
5. Servicing accessories
5.1 Special tools
The following new special tools are required for the FS 40 C-E:
8
a
5910 893
1708 A
1
2
3
901TI065 KN
The sleeve (1) of installing tool 5910 890 2208 has Flange (2) 5910 850 4200 replaces previous flange
a new camfer angle (a) of 20 degrees. The previous 1128 850 4200. The new flange has an additional
sleeve had a camfer angle of 45 degrees. The new recess on the sealing surface side.
sleeve 5910 893 1708 replaces previous sleeve
5910 893 1703.
Recommendation: Retrofit special tool
5910 890 2208 with new sleeve 5910 893 1708 and
update existing stocks of special tool 5910 890 2208
with new sleeve 5910 893 1708.
TI_22_2008_30_01_02.fm
)m~ge 8 Technical Information 22.2008
The puller (3) has a 3/8" thread and may only be The existing special tools are listed in the service
used for Series 4144 and 4140. This puller cannot manual for STIHL FS 40 C-E.
be used with metric threads because thread
damage will occur.
Item Part name Part No. Use
1 Sleeve 5910 893 1708 Installing hookless snap rings in pistons
(supplement to installing tool 5910 890 2208)
2 Flange 5910 850 4200 Engine leakage test
3 Puller 5910 893 0800 Removing the flywheel
5.2 Aids
Part name Part No. Use
Starter rope 35.8 in (910 mm) 4137 195 8200 Rewind starter
ElastoStart™ (special accessory) 0000 190 3403 Starter mechanism (handle with rope)
– Starter rope 35.8 in (910 mm) 4137 195 8200
Set of carburetor parts 4241 007 1002 Carburetor Zama C1M-S145 and
Carburetor Zama C1M-S146 (only for
California)
STIHL gear lubricant for Drive shaft in drive tube
hedge trimmers
– Tube 3 oz (80 g) 0781 120 1109
– Tube 5 oz (225 g) 0781 120 1110
NEW:
STIHL fitting paste Paste contains molybdenum sulfide and
– Tube 1.8 oz (50 g) 0781 130 1014 graphite;
Use for lubrication between the crankshaft stub
and the clutch drum
STIHL special oil Rewind spring in rewind starter,
– Bottle 3.4 fl oz (100 ml) 0781 417 1315 Bearing bore in rope rotor
Standard solvent-based degreaser not Cleaning the crankshaft stub and cone on the
containing any chlorinated or flywheel (see TI 25.2005)
halogenated hydrocarbons
6. Spare parts
Separate spare parts documentation will be
available for FS 40 C-E at market launch.
TI_22_2008_30_01_02.fm Page 5 of 11
Technical Information 22.2008 Page 9
7. Servicing
The safety instructions in the instruction manual
must be observed if the machine is started during
servicing.
7.1 Service manuals
The following manuals can be used for repairs to the
FS 40 C-E:
For engine, controls and drive shaft of the FS 40 C-E For the bearing housing of
(powerhead 4144) the FS 40, 50
Service manual Service manual Service manual
Powerhead 4144 Components 4144 CombiTools
0455 938 0123 0455 545 0123 0455 227 0123
7.2 Tightening torques 7.4 Maintenance and Repairs
The tightening torques are specified in the service
manual. 7.4.1 Barbed connectors on the carburetor
7.3 First use after long periods of storage
If the machine has been stored for a period of
several months and at temperatures below 5°C
(40 degrees) press the manual fuel pump several
times in order to purge the carburetor, wait a few
minutes, then start the engine.
Recommendation: Before storing the machine for
546TI009 KN
an extended period, always run the engine until the
carburetor is dry, otherwise the carburetor
diaphragms may malfunction – see "Storing the
machine" in the instruction manual. The carburetor has two barbed connectors (arrows)
on which the fuel hoses are seated. In order to
ensure there are no leaks in the fuel system, it is
important to follow the steps listed below:
. Install and remove fuel hoses, by hand
whenever possible, in order to avoid damage to
the barbed connector – sharp-edged pliers,
screwdrivers, etc., must not be used – nor
should fuel hoses be cut open with a knife or
similar implement.
. Do not reuse fuel hoses after disassembly,
always replace them with new hoses – fuel
hoses may be over-extended when removed.
. Install new fuel hoses dry or with the aid of press
fluid OH 723 – 0781 957 9000. Other press
fluids are not permitted and may lead to fuel
hose damage.
TI_22_2008_30_01_02.fm
)m~ge 10 Technical Information 22.2008
. When using press fluid OH 723, apply press 7.4.2 Installing the clutch drum
fluid to the ends of the hose and connectors
prior to installation.
1
Notes regarding press fluid OH 723
Press fluid OH 723 produces a lubricant film to aid
in assembly. The lubricant evaporates after a short
time allowing for a tight fit.
Never use fuel, oil or grease as a lubricant. Fuel, oil
and grease does not evaporate and may allow the
hose to slip from the connector.
546TI010 KN
For installation of the clutch drum (1), the crankshaft
stub (arrow) must be lubricated with the new fitting
paste 0781 130 1014.
a 2
546TI011 KN
Coat the crankshaft stub (2) with fitting paste in area
a = 10 mm.
Notes regarding fitting paste: If fitting paste is not
applied to the crankshaft stub or the carburetor is
improperly adjusted, the cutting tool may rotate
when the machine is idling.
The fitting paste can also be used with the previous
models FS 45, FS 55 and KM 55.
TI_22_2008_30_01_02.fm Page 6 of 11
Technical Information 22.2008 Page 11
7.5 Serial number
Code Type of Repair FS 40
C-E
8 Replace fuel tank line, tank
vent, or fuel pick-up body. 20
9 Replace intake manifold or
intake flange. 20
10 Repair or replace carburetor.
Includes fuel system testing. 30
11 Repair throttle control. 20
12 Repair or replace rewind starter. 15
546TI005 KN
13 Repair or replace clutch, clutch
shoes or clutch springs. 30
The serial number is located in two places on the 14 Replace muffler. 15
underside of the engine housing – as shown in the 15 Replace air filter or filter
illustration. housing. 15
16 Repair or replace stop switch.
Includes circuit testing. 25
7.6 Repair times 17 Replace clutch housing. 20
The specified repair times apply for trained and 18 Replace drive shaft and/or drive
qualified personnel as well as for properly equipped tube. 30
repair shops. 19 Replace bearing liner in drive
The repair times are specified in minutes. tube. 20
This table for the FS 40 C-E can be added to the 20 Replace limit stop or deflector. 15
STIHL repair times table. 22 Replace fuel tank. 20
40 Miscellaneous repairs and other
repairs not listed. 15
45 Handling allowance only-no
labor. 10
Code Type of Repair FS 40 50 No labor. -
C-E
2 Replace crankcase, crankcase
gasket or re-seal crankcase.
Includes air leak test. 50
3 Replace crankshaft main
bearing(s). Includes air leak
test. 50
4 Replace crankshaft seal(s).
Includes air leak test. 50
5 Perform engine air leak test. 30
6 Replace cylinder and/or piston.
Includes air leak test and repair
of components causing failure. 50
7 Replace ignition module or
flywheel. Includes stop circuit
test. 30
© ANDREAS STIHL AG & Co. KG, 2008 Technical Documentation
D1/MTK-ke
TI_22_2008_30_01_02.fm Page 7 of 11
Page 8 of 11
Page 9 of 11
Page 10 of 11
Page 11 of 11
Extracted from the manufacturer's 2012 service catalogue. Most of these PDFs embed fonts with a shifted character map, so the text above was recovered rather than copied — read it as a faithful but imperfect transcription, and treat the page image above each block as the authority where the two disagree — the figures exist only there, because they are vector drawings that text extraction cannot keep.