Technical Information · issue 24 of 2007
New HL 90 K Hedge Trimmer
Model Overall length
IssueTI 24/2007
Full text
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STIH)
Technical Information 24.2007
New HL 90 K Hedge Trimmer – Series 4280
Contents
1. Technical Description
2. Specifications
3. Cutting Attachment
4. Accessories
5. Service Accessories
6. Repairs
7. Spare Parts
The new STIHL HL 90 K hedge trimmer with a shorter length drive tube is another addition to the range of units
that offer the benefits of a 4-MIX® engine.
TI_24_2007_30_01_01.fm englisch / English USA
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The HL 90 K engine has a displacement of 1.1 Handle Hose
28.4 cm3 (28.8 cu.in) and a power output of
0.95 kW (1.3 bhp). This compares with the two-
stroke HL 45 which delivers a power output of
0.75 kW (1.0 bhp).
With its shorter length drive tube, the HL 90 K
combines the handling benefits of a regular hedge
trimmer with those of a long reach unit. The
following table shows the HL 90 K in a comparison
of lengths: 2
1
445TI001 KN
Model Overall length
each with 20 in / 500 mm
cutting blades (in / mm) The unit is held and controlled with the right hand on
the control handle (1) and the left hand on the
HS 81 T 43 / 1090 handle hose (2). The see-thru handle hose allows
HL 90 K 65 / 1650 for a clear view of the warning label on the drive
tube.
HL 45 66 / 1670
To ensure safe handling, the HL 90 K hedge
HL 100 K - 0° 81 / 2050 trimmer may only be used with the HL 0° gearbox.
No other gearboxes or attachments are approved.
HL 100 - 135° 98 / 2480
The STIHL HL 90 K is designed for both occasional 1.2 New Hand Guard
and professional users. Typical applications are the
same as those of the STIHL HL 45.
3
1. Technical Description
. 4-MIX® engine – method of operation and
benefits are described in detail in TI 01.2002 445TI002 KN
(FS 110).
. All engine components are equivalent to those
used in the FS 90 brushcutter.
The newly developed hand guard (3) limits the grip
area in the direction of the gearbox and blades. It
also protects the left hand from cuttings.
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Technical Information 24.2007 Page 3
1.3 Cutter Guard 1.4 Tip Guard
445TI003 KN
445TI004 KN
The cutter guard (4) on the cutter bar provides A tip guard kit is available as an option (see 4.). It
protection when cutting at leg height. will help protect the blades from damage when
working close to the ground or near walls and other
solid objects.
2. Specifications
2.1 Engine
STIHL 4-MIX® engine with gas-oil lubrication
Displacement: 28.8 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: 11.5 lbf / 1.3 Nm at 5,500 rpm
Idle speed: 2,800 rpm
Clutch
– clutch engages at: 3,700 rpm
Cut-off speed range
(electronic speed governor): 10,500 +/- 200 rpm
Rewind starter: Single pawl system
Starter rope
– diameter x length: 0.120 in x 33 1/2 in / 3.0 mm x 850 mm
Valve clearance
– Inlet: 0.004 in-0.015 in / 0.10 mm-0.40 mm
– Exhaust: 0.004 in-0.015 in / 0.10 mm-0.40 mm
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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 operated on a fuel mixture of
gasoline and engine oil.
2.3.1 Fuel
Fuel mix: see instruction manual
2.3.2 Fuel Tank
Capacity: 18 fl.oz (1.12 li.pt) / 530 cm3 (0.53 l)
2.3.3 Carburetor
All position diaphragm carburetor with integral fuel pump
Basic setting without limiter caps
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
dry, completely assembled,
with cutting attachment: 13.2 lbs / 6.0 kg
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Technical Information 24.2007 Page 5
3. Cutting Attachment
3.1 Gearbox
Overall gear ratio: 1:5.1
Angle: 0° to blade plane (straight)
No. of strokes at 10,500 rpm: 4,120 per minute
Weight with blades: 3.5 lbs / 1.6 kg
3.1.1 Angle Drive Gear
Lubricant: STIHL gear lubricant for brushcutters
Initial capacity: 0.35 oz / 9.5 g
Re-lubrication: up to 0.18 oz / 5 g
3.1.2 Blade Drive Gear
Lubricant: STIHL gear lubricant for brushcutters
Initial capacity: 0.75 oz / 21.0 g
Re-lubrication: up to 0.18 oz / 5 g
3.2 Cutting Blades
Method of operation: Double-sided
Cutting length: 20 in / 50 cm
Tooth pitch: 1.378 in / 35 mm
Tooth height: 0.787 in / 20 mm
Blade thickness: 0.089 in / 2.25 mm
3.2.1 Sharpening the Cutting Blades
Sharpening angle: 45° to blade plane
Sharpener: STIHL USG with special attachment for hedge trimmer blades
Sharpening instructions: See USG instruction manual
Grinding wheel STIHL shaped grinding wheel 5203 750 7010
Setting of scale A - 10°
Setting of scale B 0
Setting of scale C, right - 45°
Setting of scale C, left + 45°
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4. Accessories
Part Name Part No. Application
Cutter guard 4230 790 9202 Cutting Blades
Tip guard kit 4230 007 1005 Cutting Blades
Starter rope 0000 930 2211 Rewind starter
– 200 ft / 61 m roll
STIHL gear lubricant for brushcutters Angle drive gear
– 3 oz / 80 g tube 0781 120 1117
– 8 oz / 225 g tube 0781 120 1118
STIHL gear lubricant for hedge Blade drive gear
trimmers
– 3 oz / 80 g tube 0781 120 1109
– 8 oz / 225 g tube 0781 120 1110
5. Service Accessories
5.1 Special Servicing Tools
Part Name Part No. Application
Extension 4180 893 4400 Removing clutch drum and AV mount in conjunction with
puller 5910 890 4400
Removing tool 5910 890 4602 Pressing out clutch drum
Installing tool 5910 890 2208 Installing hookless snap rings in piston.
Installing tool 5910 890 2208 with the latest sleeve
5910 893 1703 can be used in place of 2206.
Sleeve 5910 893 1703 For updating older installing tool 5910 890 2208.
Stop screw: 4282 890 2700 Blocking the crankshaft
Current special servicing tools are listed in the following service manuals:
Assembly Service Manual
Powerhead, control handle STIHL Series 4180 Powerhead (basic engine)
Control handle, drive tube STIHL Series 4137 Components for HL
Gearbox, cutting blades STIHL KombiTools
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Technical Information 24.2007 Page 7
5.2 Servicing Aids
Part Name Part No. Application
Valve clearance 4180 007 1005
adjusting kit 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
Set of screws 5910 007 1060
STIHL degreaser
(32 oz. 6-pack) 7010 881 9401 Cleaning crankshaft stubs and flywheel taper
(see TI 25.2005)
STIHL engine
de-carbonizer (8 oz. 6-pack) 0781 319 8019 Removing carbon deposits from the combustion chamber
6. Repairs
If the machine is started in the course of repairs, it is
essential to observe all safety regulations and
safety precautions in the instruction manual.
See TI 49.2005 for further notes.
6.1 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, drive tube STIHL Series 4137 Components for HL
Gearbox, cutting blades STIHL KombiTools
IS-P5x26 screw for mounting hand guard to drive
tube 2.2 lbf.ft / 3 Nm
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6.2 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, drive tube STIHL Series 4137 Components for HL
Gearbox, cutting blades STIHL KombiTools
6.3 Serial Number
The serial number is located on the side of the
engine pan as shown in the illustration.
6.4 Repair Times
The repair times specified for the HL 100 and
HL 100 K can be used for the HL 90 K.
7. Spare Parts
Spare parts documentation will be available for the
new machine’s market launch.
The new machine is included in the STIHL Service
Communication System (MediaCat CD-ROM) from
issue 02/2007.
© ANDREAS STIHL AG & Co. KG, 2007 Technical Documentation
D1/MTK-na
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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.