Technical Information · issue 49 of 2005
New STIHL KM 90 KombiEngine
IssueTI 49/2005
Full text
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STIH)
Technical Information 49.2005
New STIHL KM 90 KombiEngine – Series 4180
Contents
1. Technical Description
2. Specifications
3. KombiTools
4. Accessories
5. Repairs
6. Spare Parts
The KM 90 KombiEngine with 4-MIX® engine is the
latest addition to the STIHL KombiSystem.
The range of applications is the same as for the
KM 55, KM 85 and KM 110 KombiEngines.
The engine has a displacement of 1.73 cu.in
(28.4 cm3) and a power output of 1.3 bhp (0.95 kW).
The basic KombiEngine with drive tube is available
with a with a loop handle (KM 90 R).
KombiTools can be attached to the KombiEngine’s
drive tube. A wide selection of STIHL KombiTools is
available – see assignment table in chapter 4. The
quick-action coupling is designed so that the shafts
self-align without any additional twisting and turning.
KombiEngine and KombiTool take up a minimum of
space for easy transportation and storage.
TI_49_2005_30_01_01.fm englisch / English USA
)m~ge 2 Technical Information 49.2005
1. Technical Description 1.2 Tank Cap
. 4-MIX® engine – method of operation and
benefits are described in detail in TI 01.2002
(FS 110).
. All engine components are similar to those used
in the KM 110. The differences brought about by
the smaller displacement of the KM 90 affect the
cylinder with piston, carburetor with spacer
flange, muffler and fuel tank.
. The fan housing is made of polymer – as on
models FS 100 RX and FC 100.
. The ergonomically shaped control handle, left
handle and drive tube are the same as those on The tank cap is designed for quick and simple
the KM 110. opening and closing.
1.1 Drive Tube / Drive Shafts
393TI005 KN
. Drive tube with rigid drive shaft
. Quickly disassembled for space-saving
transportation
. Fast KombiTool changes
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Technical Information 49.2005 Page 3
2. Specifications
2.1 Powerhead
STIHL 4-MIX engine with gas-oil lubrication
Displacement: 1.73 cu in (28.4 cm3)
Bore: 1.5 in (38 mm)
Stroke: 0.98 in (25 mm)
Engine power to ISO 8893: 1.3 bhp (0.95 kW) at 7,000 rpm
Torque: 0.96 lbf ft (1.3 Nm) at 5,500 rpm
Idle speed: 2,800 rpm
Clutch
– clutch engages at: 3,700 rpm
Cut-off speed
(electronic speed governor): 10,500 +/- 200 rpm
Rewind starter: Single pawl system
Starter rope
– diameter x length: 0.12 in x 33 1/2 in (3.0 mm x 850 mm)
Valve clearance
- Inlet: 0.004 in-0.015 in (0.1 mm-0.4 mm)
- Exhaust: 0.004 in-0.015 in (0.1 mm-0.4 mm)
2.2 Ignition System
Ignition module with integral electronic speed governor
Spark plug (resistor type): Bosch USR 7AC
Electrode gap: 0.02 in (0.5 mm)
2.3 Fuel System
The STIHL 4-MIX® engine features gasoline-oil lubrication and must be run on a fuel mixture of gasoline and
air cooled 2-cycle engine mix oil.
2.3.1 Fuel
Fuel mix: 50:1 with STIHL 2-cycle mix oil
2.3.2 Fuel Tank
Capacity: 18.0 fl oz (530 cm3)
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)m~ge 4 Technical Information 49.2005
2.3.3 Carburetor
All position diaphragm carburetor with integral fuel pump
Basic setting without limiter caps (when performing repairs)
Low speed screw L: Open 1 turn
High speed screw H: Open 3.5 turns
Standard setting with limiter caps
Low speed screw L: Open 3/4 turn (no further than stop)
High speed screw H: Open 3/4 turn (no further than stop)
2.4 Weight
2.4.1 KombiEngine
Dry, without KombiTool
– KM 90 R: 9.9 lbs (4.5 kg)
2.4.2 KombiTool
without KombiEngine with tool and deflector
BF-KM 9.0 lbs (4.1 kg)
FCB-KM 4.9 lbs (2.2 kg)
FCS-KM 5.7 lbs (2.6 kg)
FH-KM (135°) 5.3 lbs (2.4 kg)
FS-KM 2.6 lbs (1.2 kg), without cutting tool and deflector
HL-KM 0° 4.0 lbs (1.8 kg) / 5.1 lbs (2.3 kg) 1)
HL-KM 135°, adjustable 5.7 lbs (2.6 kg)
HT-KM 4.0 lbs (1.8 kg)
KB-KM (4601) 14.1 lbs (6.4 kg)
KW-KM (4601) 16.3 lbs (7.4 kg)
1)
Previous version
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Technical Information 49.2005 Page 5
3. KombiTools
The following STIHL KombiTools are approved:
KombiTool Application
FS-KM Brushcutter with mowing
head
FS-KM 1) Brushcutter with metal
cutting tool
HL-KM 0..90° 1) 2) 3) Hedge trimmer, adjustable
HL-KM 135° 1) 2) Hedge trimmer, adjustable
2)
HL-KM 0° Hedge trimmer
FH-KM 1) Power scythe
2)
HT-KM Pole pruner
BF-KM 1) Cultivator, pick tines
2)
FCB-KM Power edger, curved drive
tube
FCS-KM 2) Power edger, straight drive
tube
KB-KM (4601) 2) Bristle brush
KW-KM (4601) 2) PowerSweep
1)
Loop handle must be equipped with barrier bar
2)
Not approved for KombiEngines with bike
handle
3) No longer available from factory
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)m~ge 6 Technical Information 49.2005
3.1 Cutting Tools for FS-KM KombiTool
The FS-KM KombiTool is available with the following
cutting tools:
1 STIHL AUTOCUT® 25-2 4002 710 2108
mowing head
2 Grass cutting blade 230-4 4001 713 3801
1 2
461TI003 BL
3.1.1 Assignment of Cutting Tools to FS-KM
KombiTool
Kombi- Handle FS-KM KombiTool with
Engine
Mowing Grass cutting blade Brush knife Circular saw
head blade
KM 90 R + + + –
+ approved
– not approved
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Technical Information 49.2005 Page 7
4. Accessories
4.1 Accessories for User
Same as model KM 110 R.
4.2 Service Accessories
4.2.1 Special Servicing Tools
Part Name Part No. Application
Extension 4180 893 4400 Removing clutch drum and AV element in conjunction
with puller 5910 890 4400
Removing tool 5910 890 4602 Pressing out clutch drum
Installing tool 5910 890 2206 Installing hookless snap rings (piston boss).
Installing tool 5910 890 2208 with the latest sleeve
5910 893 1703 can be used in place of 2206.
Sleeve 5910 893 1703 Installing hookless snap rings (piston boss) in
conjunction with installing tool 5910 890 2208
Piston Stop
– previous: 4180 890 2700
– new: 4282 890 2700 Blocking the crankshaft
Existing special servicing tools are listed in the following service manuals:
Assembly Service Manual
Powerhead, control handle STIHL Series 4180 Powerhead (basic engine)
Control handle, handle, drive tube STIHL Series 4137 Components, FS 85
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4.2.2 Servicing Aids
Part Name Part No. Application
Valve clearance
adjusting kit 4180 007 1005 Checking and adjusting valve clearances
Set of gaskets 4180 007 1006 Engine
Carburetor parts kit 4180 007 1060 C1Q-S110
Lubricating grease,
8 oz (225 g) tube 0781 120 1111 Oil seals
Dirko HT sealant, red
3.2 oz (90 g) tube 0783 830 2000 Sealing engine pan/cylinder, cylinder/cam gear cover
Electrical repair kit 5910 007 1050 Electrical system
Set of screws 5910 007 1060 Engine
Press Fluid OH 723,
3.4 fl oz (100 ml) bottle 0781 957 9000 Rubber elements of AV system, connector, fuel hose
Standard commercial, solvent-
based degreasant without
chlorinated or halogenated
hydrocarbons Cleaning crankshaft stubs and flywheel taper
(see TI 25.2005)
5. Repairs 5.2 Leakage Test
If the machine is started up in the course of repairs, Leaks are caused by defective oil seals and gaskets
it is essential to observe all country-specific safety or cracks in castings. Such faults may allow
regulations and the safety precautions outlined in supplementary air to enter the engine and change
the instruction manual. the air-fuel-oil mixture.
This can upset the lubricating process or cause it to
fail.
5.1 Checking Valve Clearance The engine can be tested for leaks with the
Check and adjust valve clearance only when the carburetor/crankcase tester and vacuum pump.
engine is cold. Use the valve clearance adjusting kit Carry out the leakage test as for model FS 110 (see
4180 007 1005 (consisting of feeler gauge, sealing TI 01.2002 or the service manual for Series 4180
ring and gasket) for this purpose. Powerhead).
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Technical Information 49.2005 Page 9
5.3 Clutch Drum
. Remove the fan housing. 5
249TI023 KN
4
. Take out the screw (4).
. Use a suitable arbor to press the ball bearing (5)
. Remove the circlip (1). out of its seat.
. Press home the new ball bearing with press
arbor 4119 893 7200.
. Tighten the screw (4) to 4 Nm (35 in. lbs.).
. Reassemble in the reverse sequence.
2
5.4 Fuel Tank, Hose
249TI021 KN
. Support the ball bearing at the clutch drum side
with removing tool (2) 5910 890 4602.
. Turn over the removing tool together with the fan
housing – fan housing rests on the removing
tool.
The fuel hose system consists of the pickup body
(1), molded hose (2), connector (3), suction hose (4)
and return hose (5).
249TI022 KN
Hoses (4) and (5) can be cut to length from the
“3.1 x 5.7 mm hose“ which is supplied by the meter.
. Insert extension (3) 4180 893 4400 in the
square hole and press the clutch drum out of the
bearing seat.
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)m~ge 10 Technical Information 49.2005
5.4.1 Replacing Fuel Pickup Body
It is necessary to remove the connector in order to
replace the fuel pickup body.
5.4.2 Removing the Connector
. Center the connector in the bore – as shown in
the illustration.
. Press home the connector squarely as far as
stop – it must snap into position.
Insert a suitable under the tab (a) and pry the
connector out of the tank.
5.4.3 Installing the Connector
. Coat O-ring and bead of connector with
Press Fluid 0781 957 9000. . Push one end of the suction hose (1) onto the
stub with the choke symbol and then fit the other
end on the fuel intake (2).
. Push the hose (3) onto connector (4) and the
return stub (5).
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Technical Information 49.2005 Page 11
5.5 Tightening Torques
The tightening torques are listed in the following service manuals:
Assembly Service Manual
Powerhead, control handle STIHL Series 4180 Powerhead (basic engine)
Control handle, handle, drive tube STIHL Series 4137 Components, FS 85
5.6 Service Note
The following service manuals are available for servicing and repairs:
Assembly Service Manual
Powerhead STIHL Service Training System “Diagnosis”
Powerhead, control handle STIHL Series 4180 Powerhead (basic engine)
Control handle, handle, drive tube STIHL Series 4137 Components, FS 85
5.7 Serial Number 5.8 Repair Times
The repair times for the KM 110 KombiEngine also
apply for the KM 90 KombiEngine – see repair times
table for KM 110.
The serial number is located on the side of the
engine pan as shown in the illustration.
6. Spare Parts
Spare parts documentation is already available for
the new machine.
The new machine is included in the STIHL Service
Communication Systems (MediaCat CD-ROM) from
issue 01/2006.
© ANDREAS STIHL AG & Co. KG, 2005 Technical Documentation
D1/MTK-na
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