Technical Information · issue 29 of 2003
Technical Description; Specifications; Cutting Too
IssueTI 29/2003
Full text
Page 1 of 18
STIH)
Technical Information
29.2003
New Model FS 110 Brushcutter – Series 4180
Contents
1.
2.
Technical Description
Specifications
3. Cutting Tools
4. Accessories
5. Service Accessories
6. Service Note
7. Spare Parts
FS 110 R FS 110 R FS 110
TI_29_2003_01_01_01.fm englisch / english
)m~ge 2 Technical Information 29.2003
The new STIHL FS 110 brushcutter with 4-MIX
engine is the latest addition to the semi-professional
range.
The new 4-MIX engine operates with the patented
STIHL lubricating system. Gas flow is controlled
according to the four-stroke principle. The STIHL
4-MIX engine uses the same fuel mixture as STIHL
two-stroke engines.
The engine has a displacement of 31,4 cm3 and a
power output of 1,0 kW.
The range of applications is the same as for model
FS 85 brushcutters.
1. Technical Description
254BA016 KN
1.1 STIHL 4-MIX Engine
The 4-MIX engine features gas-oil lubrication.
Compared to a conventional four-stroke engine, the
4-MIX engine has no separate oil supply in the 1.1.2 Valve Timing Gear
crankcase. Engine lubrication is effected by way the
fuel mixture of gasoline and engine oil.
The benefits of this new concept are: 7
. Familiar fuel mix
. Favorable fuel consumption
. Operates in all positions 1 2
. Reduced emissions 6
. Good acceleration 5
. Compact construction – attractive design
. Favorable power-to-weight ratio 4
. Simple maintenance – service-friendly
. More pleasant engine note – lower noise level
. Lower vibrations 3
254TI011 KN
. Reduced cranking effort
1.1.1 Engine Construction . Overhead valves (OHV), one inlet valve (1) and
Single cylinder engine with overhead valves. one exhaust valve (2)
Cylinder head, cylinder and the upper half of the . Valve timing via gear (3), cam (4), cam
crankcase form a single block. follower (5), pushrod (6) and rocker arm (7)
The crankcase is split horizontally along the
crankshaft centerline. . Cross-flow scavenging
(= inlet and exhaust sides opposite one another)
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Technical Information 29.2003 Page 3
1.1.3 Engine Lubrication
The lubricating process takes place in two phases
during one revolution of the crankshaft.
Phase 1 Phase 2
Piston moves in direction of top dead center. Piston moves in direction of bottom dead center.
5 fo
254TI017 KN
254TI019 KN
The increase in volume in the crankcase creates a Over-pressure is created by the reduction in volume
depression. Gasoline-oil-air mixture is sucked in in the crankcase.
from the inlet port (1) and flows via the bypass
This causes the gasoline-oil-air mixture in the
bore (2), valve gear (3) and timing gear (4) to the
crankcase to be forced back through the timing
crankcase (5). The oil in the mixture lubricates the
gear, valve gear and the bypass bore to the inlet
crankgear, timing gear, valve gear and the cylinder
port. All lubricating points are wetted again in this
wall.
process.
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)m~ge 4 Technical Information 29.2003
1.2 Tank Cap
The new tank cap with a hinged clip is designed for
quick and simple opening and closing.
1.2.1 Opening 1.2.2 Closing
254TI020 KN
254TI022 KN
. Swing the clip up to the vertical position. . Place the cap in position with the clip vertical –
the marks must line up.
.
Rotate the cap about 1/4 turn clockwise.
254TI021 KN
254TI023 KN
. Rotate the cap about 1/4 turn counterclockwise.
. Remove the tank cap.
. Fold the clip down so that it is level with the top
edge of the cap.
The tank cap is properly locked in position when the
clip’s lug engages the recess (see arrow in right
illustration).
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Technical Information 29.2003 Page 5
2. Specifications
2.1 Powerhead Mix ratio:
STIHL single cylinder four-stroke engine with 50:1 with STIHL 50:1 two-stroke engine oil
gas-oil lubrication 25:1 with other branded two-stroke engine oils
Displacement: 31,4 cm3 Carburetor:
Bore: 40 mm All position diaphragm carburetor with integral fuel
Stroke: 25 mm pump
Engine power to 1 kW at
ISO 8893: 7.000 rpm Low speed screw L
Idle speed: 2.800 rpm (standard setting with
Rewind starter: Single pawl system caps): Open max. 3/4 turn
Starter rope: 3 mm diameter, (as far as stop)
850 mm long (Standard setting without
caps): Open 3 turns
Clutch engages at: 3.700 rpm
High speed screw H
Valve clearance
(standard setting with
Inlet: 0,10 mm
caps): Max. 3/4 turn
Exhaust: 0,10 mm
(as far as stop)
2.2 Ignition System fo
(Standard setting without
caps): Open 2 turns
Ignition module: with integral electronic Cut-off speed without tool
speed governor
(electronic speed
Spark plug NGK CMR 5 H governor): 10.500 +/- 500 rpm
(suppressed): Bosch USR 7AC 530 cm3
Fuel tank capacity:
Electrode gap: 0,7 mm
2.3 Fuel System
2.4 Gearhead
The STIHL 4-MIX engine features gasoline-oil
Gear ratio:
lubrication and must be run on a fuel mixture of
FS 110 and FS 110 R 1:1,4
gasoline and engine oil.
Fuel mix: 2.5 Weight
Brand-name regular grade gasoline (leaded or
unleaded) and branded two-stroke engine oil. without cutting tool and
deflector
FS 110: 5,7 kg
FS 110 R: 5,5 kg
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)m~ge 6 Technical Information 29.2003
3. Cutting Tools
The following cutting tools are approved
1 STIHL Supercut 20-2
mowing head 4002 710 2162 1 2
2 STIHL Autocut 21-2
mowing head 4002 710 2113
3 STIHL Autocut 25-2
mowing head 4002 710 2108
4 STIHL Trimcut 30-2 3 4
mowing head 4002 710 2122
5 STIHL Polycut 20-3
mowing head 4002 710 2130
5
6 Grass cutting blade 230-2 1) 4001 713 3805
7 Grass cutting blade 230-4 1) 4001 713 3801
8 Grass cutting blade 230-8 1) 4001 713 3803
9 Brush knife 250-3 1) 4112 713 4100
10 Circular saw blade 200 4112 713 4201 6 7
(scratcher tooth) 2)
11 Circular saw blade 200
(chisel tool) 2)
4112 713 4203 fo
8 9
1) Not approved for loop-handled FS 110
without barrier bar
2) Not approved for FS 110
with loop handle
10 11
393TI006 KN
All the cutting tools listed above must be used with
the recommended deflector and/or barrier bar
(see catalog "Cutting Attachments").
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Technical Information 29.2003 Page 7
4. Accessories
4.1 General
Part Name Part No. Application
Transport guard for 4116 790 3901 Grass cutting blade 230-2, 230-4, 230-8,
metal cutting tools brush knife 250-3, circular saw blade 200
4119 790 3906 Grass cutting blade 230-2, 230-4, 230-8,
brush knife 250-3
4119 790 3901 Circular saw blade 200
Starter rope 0000 195 8203 Rewind starter
STIHL gear lubricant for Gearbox
brushcutters
- 80 g tube 0781 120 1117
- 225 g tube 0781 120 1118
STIHL special oil Rewind spring in starter,
- 100 ml bottle 0781 417 1315 bearing bore in rope rotor
4.2 Nylon line for mowing head
Diameter / color Application
2,4 mm / orange SuperCut 20-2, AutoCut 21-2, AutoCut 25-2, TrimCut 30-2, PolyCut 20-3
2,7 mm / red PolyCut 20-3
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)m~ge 8 Technical Information 29.2003
5. Service Accessories
5.1 Special Servicing Tools
Required for model FS 110
Part Name Part No. Application
Compression pressure tester 5910 850 2000 Checking compression pressure
Extension 4180 893 4400 Removing clutch drum and AV element in
conjunction with puller 5910 890 4400
Installing tool 5910 890 2206 Installing hookless snap rings (piston boss)
Sleeve 5910 893 1703 Installing hookless snap rings (piston boss) in
conjunction with installing tool 5910 890 2208
Feeler gauge 4180 893 6400 Checking, adjusting valve clearance
Stop screw 4180 890 2700 Blocking the crankshaft
Existing special servicing tools are listed in the service manual for the STIHL series 4180 powerhead (basic
engine).
5.2 Servicing Aids fo
Part Name Part No. Application
Valve clearance adjusting kit 4180 007 1005 Checking, adjusting valve clearance
Set of gaskets 4180 007 1006 Engine
Carburetor parts kit 4180 007 1060 Carburetor
Lubricating grease (225 g tube) 0781 120 1111 Oil seals
Dirko sealant 0783 830 2120 Sealing engine pan/cylinder, cylinder/cam gear
cover
Press fluid 0781 957 9000 Rubber elements of AV system
Standard commercial, solvent- Cleaning the crankshaft stub
based degreasant without
chlorinated or halogenated
hydrocarbons
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Technical Information 29.2003 Page 9
6. Service Note
If the machine is started up in the course of repairs,
it is essential to observe all country-specific safety
regulations and the safety precautions outlined in 6
the instruction manual.
6.1 Checking Valve Clearance
5
The valve clearance must be checked once after
about 135 hours of operation and adjusted if 4
254TI002 KN
necessary. 4
Check and adjust valve clearance only when the
engine is cold. Use the valve clearance adjusting kit
4180 007 1005 (consisting of feeler gauge, sealing . Take out the screws (4).
ring and gasket) for this purpose. . Remove the shroud (5).
. Pull off the spark plug boot (6).
6.1.1 Preparations
. Clean the area around the spark plug.
It is easier to move the piston to top center on the
ignition stroke when the rewind starter is removed. . Unscrew the spark plug.
However, it is also possible to turn the crankshaft
with the starter with the starter cover mounted.
7
3
8
1 1
2
9
254TI001 KN
. Push the slide control in direction of c (arrow)
to STOP– $.
. Take out the screws (1). 10
254TI003 KN
. Remove the starter cover (2) from the housing.
. Take out the screw (3).
. Clean area around the valve cover.
. Take out the screw (7).
. Remove the sealing ring (8), valve cover (9) and
gasket (10).
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)m~ge 10 Technical Information 29.2003
6.1.2 Top Dead Center
Top dead center (T.D.C.) is the point at which the
movement of the piston changes from upwards to
downwards. In the 4-MIX engine the power stroke
takes place once every two revolutions of the
crankshaft. As a result, the piston passes through
top dead center twice but performs only one power
stroke. See STIHL Service Training System
"Carburetor", four-stroke principle.
Top Dead Center, Valve Overlap Top Dead Center, Ignition
2
2
3 3
1 1
254TI010 KN
254TI009 KN
Cam (1) points up. Cam (1) points down.
The rocker arms (2) and valve stems (3) move up The rocker arms (2) and valve stems (3) do not
and down (see top arrows) when the crankshaft is move up and down when the crankshaft is turned
turned back and forth a few degrees. back and forth a few degrees.
This is the change in stroke between exhaust and This is the change in stroke between compression
induction. and power.
Valve clearance must be adjusted at top dead
center on the ignition stroke. It is only in the
position that inlet and exhaust valves are closed at
the same time.
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Technical Information 29.2003 Page 11
6.1.3 Determining Top Dead Center 6.1.4 Checking Valve Clearance
The cam gear cover must be removed to check and
adjust valve clearance.
2
1 2
1
3
254TI008 KN
. Rotate the crankshaft until the arrow (1) is in line
with the right-hand screw head (2) on the
ignition coil.
2
The piston is now at top dead center, either on valve
overlap or ignition.
254TI005 KN
1
. Insert the feeler gauge (1) between the rocker
arm (2) and valve stem (3). The feeler gauge
must move with slight resistance.
Readjust valve clearance if the check shows it to be
excessive or insufficient.
6.2 Adjusting Valve Clearance
254TI004 KN
. Turn the crankshaft back and forth a few
degrees – if the rocker arms und valve stems
(see arrows) move up and down, the piston is at 2
top dead center on valve overlap.
. Rotate the crankshaft one more revolution until
the arrow again lines up with the right-hand
screw head on the ignition coil.
254TI006 KN
If the rocker arms and valve stems do not move, the 1
piston is at top dead center on the ignition stroke.
. Turn the crankshaft back about 1/4 revolution . Insert the feeler gauge (1) between the rocker
counterclockwise and then turn it slowly arm and valve stem.
clockwise until the arrow is in line with the right- Depending on current clearance
hand screw head.
. Turn nut (2) clockwise clockwise to reduce valve
clearance or counterclockwise to increase valve
It is necessary to turn the crankshaft back to clearance – the feeler gauge must slide back
eliminate play in the timing gear. and forth with slight resistance.
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)m~ge 12 Technical Information 29.2003
. Rotate crankshaft two revolutions until the 6.4 Setting the carburetor
arrow again lines up with the right-hand screw The carburetor is set to a standard setting by the
head on the ignition coil. manufacturer.
. Check valve clearance again and readjust if This setting ensures an optimum fuel-air mixture
necessary. under almost all operating conditions.
6.3 Assembling With this carburetor, it is only possible to correct the
adjustment of the high speed and low speed screws
Use sealing ring and gasket supplied in the valve
within fine limits.
clearance adjusting kit 4180 007 1005.
6.4.1 Construction
5
1
2
254TI007 KN
249TI002 KN
. Place the gasket (1) on the sealing face and
make sure it is properly positioned (see arrows). 6 3 4
. Fit the valve cover and tighten down the screw . Low speed screw (1)
to 3,5 Nm.
. Cap for low speed screw (2)
. Install spark plug, shroud and spark plug boot.
. High speed screw (3)
. Fit the starter cover and tighten down the
screws firmly. . Cap for high speed screw (4)
. Start the engine and allow it to warm up. . Stop (5)
. Shut off the engine. . Idle speed screw (6) with cap
. Check engine for leaks.
The caps are pushed over the heads of the
adjusting screws and onto the knurling. The stop (5)
on the carburetor body limits screw rotation.
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Technical Information 29.2003 Page 13
6.4.2 Function Standard setting
H L
270° 270°
249TI004 KN
249TI006 KN
The caps limit the range of adjustment of the high . Starting with the adjusting screws against their
speed and low speed screws to 270 degrees (3/4 of seats:
a turn).
Open H screw 2 full turns.
6.4.3 Service / repair
Open L screw 3 full turns.
2 fo
Secure caps
H L
249TI005 KN
The caps must be removed in order to replace a
249TI007 KN
damaged adjusting screw or to clean the carburetor.
. Push the puller 5910 890 4501 (1) between the
cap (2) and carburetor housing with the groove Do not refit used caps
facing the cap.
. Fit the new caps in position so that they butt
. Prise off the cap. If the cap remains stuck on the against the rich stop (see arrow) and press
adjusting screw, turn the puller over so that the them down until the second detent is clearly
groove faces the carburetor housing and prise felt.
the cap off again. Do not press the caps right down onto the
Do not refit used caps. carburetor housing, otherwise they will be
damaged.
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)m~ge 14 Technical Information 29.2003
Adjust idle speed 6.5 Accelerator pump
4
H L
2 a
1 3
9
8
249TI010 KN
249TI009 KN
LA 7
6
5
The carburetor is equipped with an accelerator
. Set engine speed to 2800 rpm with the idle
pump. The pump piston (6) is located in the bore (a)
speed screw (LA).
behind the throttle shaft (4) and is held in the idle
The adjustment must be checked with a position by a compression spring (8).
tachometer – the 4-MIX engine produces a spark
Strainer (5) is installed in the bore (a) in front of the
with every revolution of the crankshaft.
throttle shaft (4) to keep out dirt.
Check running behaviour
. Open the throttle several times to check that the
Disassembling the accelerator pump
engine accelerates properly and runs smoothly . Take out the screw (1).
at idle speed.
. Remove the throttle shutter (2).
Engine idles erratically
. Remove the E-clip (3).
. Turn the low speed screw (L) clockwise (no
. Take out the strainer (5).
further than stop) until the engine runs smoothly
and acceleration is still good. . Hold the bore (a) closed with one finger.
. Push back the throttle shaft with lever (4) until
6.4.4 Setting instructions for users
the end of the throttle shaft is visible in the
The user can only adjust the screws within a range venturi.
of 270 degrees. . Carefully expose the bore (a) – then remove the
This allows the carburetor to be tuned to different pump piston (6) with sealing ring (7) and
working conditions, such as: spring (8).
– Change of altitude (mountainous country) . Take out and examine the strainer (9) –
replace if it is dirty or damaged.
– Change of tools
. Inspect the pump piston (6) and spring (8) –
The procedure for setting the carburetor is
replace if damaged.
described in the owner's manuals for the respective
machines (see "Adjusting the carburetor"). . Fit a new sealing ring (7) in the groove of the
pump piston (6).
. Reassemble parts in reverse order.
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Technical Information 29.2003 Page 15
6.6 Power unit 6.6.2 Leakage test
Check the compression pressure and absence of Defective oil seals and gaskets or cracks in castings
leaks in the power unit in order to locate any faults cause leaks. Such faults allow supplementary air to
in the power unit. enter the engine and change the fuel-oil-air mixture.
The air filter, spark arresting screen, fuel supply, This can upset the lubricating process or cause it to
carburetor and ignition system must be checked fail altogether.
before attempting to locate faults in the power unit.
The engine can be checked for leaks with the
carburetor and crankcase tester and the vacuum
6.6.1 Check compression pressure
pump.
. Pull the boot off the spark plug and then
Preparations
unscrew the spark plug.
. Move the slide control to STOP– $.
. Remove the shroud.
. Remove the filter cover and air filter.
1 . Remove the filter housing and pull off the
gasket.
. To release tank pressure, open the tank cap and
then close it again.
. fo
Disconnect the fuel hoses and the impulse hose
249TI013 KN
from the carburetor.
. Disconnect the throttle cable.
. Screw compression pressure tester . Pull off the carburetor.
5910 850 2000 (1) into the spark plug hole.
1
. Move slide control to STOP– $.
. Set choke to e ("open"). 2
. Pull the starter rope several times – firmly and
quickly as for a normal start. 3
. Note the compression pressure reading –
it should be 6–7 bar. 4
5
If the pressure is less than 6 bar:
249TI014 KN
. Check valve clearance, readjust if necessary
and check compression pressure again.
If the pressure is still less than 6 bar: . Push the test flange (1) 1119 850 4201 into
position.
. Inspect cylinder, valve seat, piston and rings for
scores and damage. . Fit the sleeves (2) 0000 963 1008 and nuts (3)
and tighten down firmly.
. Use a suitable plug (5) to seal the impulse
hose (4).
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)m~ge 16 Technical Information 29.2003
Vacuum test
1 Oil seals tend to fail when subjected to a vacuum,
i.e. the sealing lip lifts away from the crankshaft
during the piston's induction stroke because there is
no internal counterpressure.
249TI015 KN
. Loosen the muffler mounting screws.
. Insert the sealing plate (1) 0000 855 8106
between the exhaust gasket and the muffler –
249TI016 KN
the sealing plate must cover the muffler opening
completely.
. Tighten down the screws. . Connect suction hose (arrow) of vacuum pump
. Continue with "Pressure test". 0000 850 3501 to nipple of test flange.
Pressure test
.
.
Close the vent screw on the pump cylinder.
Operate vacuum pump until the pressure gauge
indicates a vacuum of 0,5 bar.
. If the vacuum reading remains constant or does
not drop to less than 0,3 bar within 20 seconds,
it can be assumed that the oil seals are in good
condition.
If the pressure continues to rise, the oil seals must
be replaced.
sio 249TI016 KN
. Connect pressure hose of tester 1106 850 2905
to nipple on test flange (arrow).
. Close the vent screw on the rubber bulb.
. Pump air into the engine housing with the rubber
bulb until the gauge indicates a pressure of
0,5 bar. If this pressure remains constant for at
least 20 seconds, the engine housing is airtight.
. If the pressure drops, the leak must be found
and the faulty part replaced.
. To find the leak, coat the suspect area with oil
and pressurize the engine housing again.
Bubbles will appear if a leak exists.
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Technical Information 29.2003 Page 17
6.7 Adjusting the throttle cable
Important: Carry out this adjustment only after the
machine has been properly and securely
assembled – the handlebar and control handle must STO
be in the normal operating position. Proper
adjustment of the throttle cable is the necessary for
correct operation in the full throttle, starting throttle
2
and idle positions.
254TI014 KN
1
. Squeeze the interlock lever (1) and throttle
trigger (2) all the way (full throttle) – this sets the
throttle cable correctly – the slide moves away
from the bottom of the slot.
254TI013 KN
. Use a screwdriver to push the slide to the
bottom of the slot.
254TI015 KN
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)m~ge 18 Technical Information 29.2003
6.8 Tightening Torques
Tightening torques for the FS 110 are listed in the Repair procedure FS 110
service manual for the STIHL series 4180
powerhead (basic engine). 1 Remove and refit engine 10
2 Crankcase, pressure test* 100
6.9 Service Note 3 Crankshaft, bearings, 100
For servicing and repair procedures on the FS 110 pressure test*
refer to the service manual for the STIHL series 4 Sealing rings, pressure test* -
4180 powerhead; see also STIHL Service Training 5 Crankcase leakage test, test run 40
System "Diagnosis". 6 Cylinder, piston, pressure test* -
7 Ignition system, contact* 15
6.10 Repair Times
8 Fuel supply, tank vent, 10
The specified repair times assume that the work is test run
performed by trained personnel in a properly 9 Manifold or flange, -
equipped service workshop.
pressure test
The repair times are given in minutes. 10 Carburetor, check* 30
This table for the FS 110 can be added to the STIHL 11 Handle and throttle control 10
repair times table. 12 Rewind starter, test run 15
13 Clutch, test run 20
7. Spare Parts 14
15
Muffler
Air filter
10
5
A separate illustrated parts list is available for the
16 Stop switch, test run 10
new model.
17 Clutch housing -
18 Drive tube 20
19 Replace gearhead or bearing 5
housing
20 Limit stop or deflector 10
21 Drive shaft 10
22 Fuel tank 15
23 Check compression pressure 5
24 Adjust valve clearance 10
25 Replace crankcase, 150
bottom half
26 Replace crankshaft 160
27 Replace cylinder, piston 180
28 Oil supply -
29 Oil pump, test run -
!
* Test run under load
© ANDREAS STIHL AG & Co. KG, 2003 Technische Dokumentation
D1/MTK-bl 7870
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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.