Technical Information · issue 44 of 1999

HS 45: New Model Hedge Trimmer

IssueTI 44/1999

Part changes (1)

Was	Becomes	What the bulletin says
0781 120 1110	1120 195 8200	STIHL gear lubricant for hedge Gearbox trimmers - 80 g tube 0781 120 1109 - 225 g tube 0781 120 1110 * For model HS 45, the 3 x 800mm starter rope which comes as standard with the ElastoStart must be replaced by a 3 x 1060mm starter rope (1120 195 8200).

Full text

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Technical Information

44.1999
New Model HS 45 Hedge Trimmer - Series 4228

Contents
1. Technical Description
2. Specifications
3. Special Accessories
4. Service Accessories
5. Repairs
6. Spare Parts

The new HS 45 lightweight hedge trimmer rounds The HS 45 features a new cutting blade construction
off the lower end of the line of hedge trimmers. with an integral blade guard. Available cutting
The engine is enclosed in a compact, smooth- lengths are 18 and 24 inches.
contoured housing made of high impact polymer. The HS 45 is designed for occasional users.
Ergonomically designed controls and a favorable Typical applications are cutting and shaping
power to weight ratio for easy handling and less hedges.
operator fatigue.

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)m~ge 2 Technical Information 44.1999

1. Technical Description
Crankshaft
. Composite crankshaft to form a torsionally rigid
assembly.
. Both ends supported in bearings.

Cylinder
. Four port technology (better mixture control,
clean combustion, lower emissions).
. Large cooling area.

Carburetor
. Only one adjusting screw (LD).
. Balanced idle system with fixed idle jet*.
. Fixed full-load jet

Air filter
. Improved filter material
. Large filter surface area

Exhaust muffler
. Dual-chamber muffler

Controls
. Integrated in rear handle

Clutch
. Two clutch shoes without linings

Cutting blades
. New blade geometry
. Integral blade guard

Gearbox
. Cutting blades driven directly by spur gear cam
(no conrod)
. Fewer parts
. Simple servicing

* Balanced idle system is described in detail in the “Carburetors” handbook.

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Technical Information 44.1999                                                                   Page 3

2.    Specifications

2.1   Powerhead

2.1.1 Engine
Single cylinder two-stroke engine
Displacement:             27.2 cm3 (1.66 cu.in)
Bore:                     34 mm (1.34 in)
Stroke:                   30 mm (1.10 in)
Engine power to           0.75 kW (1 HP)
ISO 8893:                 at 7,000 rpm
Engine speeds:            see 2.1.2
Rewind starter:           Single pawl system
Starter rope:             3 mm (0.12 in) dia.,
                          800 mm (31.5 in) long

2.1.2 Fuel System
Carburetor: All position diaphragm carburetor with integral fuel pump

Idle speed screw LD (standard setting)                            Open 2 full turns (see 5.1)
Idle speed                                                        2,500 to 3,100 rpm
Cutoff speed range (electronic speed governor)                    8,700 to 10,300 rpm

Fuel tank capacity:         0.225 L (0.47 US pt)

2.1.3 Ignition System

Ignition module:        with integral electronic speed
                        governor
Spark plug              Bosch WSR 6F,
(suppressed):           NGK BPMR 7 A or
                        Champion RCJ 6Y

2.2   Weight

HS 45 with 18“ blade:             10.1 lbs (4.6 kg)
HS 45 with 24“ blade:             10.8 lbs (4.9 kg)

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3.    Special Accessories
Part Name                           Part No.              Application
ElastoStart*                        0000 190 3400         Rewind starter

STIHL gear lubricant for hedge                            Gearbox
trimmers
- 80 g tube                         0781 120 1109
- 225 g tube                        0781 120 1110

* For model HS 45, the 3 x 800mm starter rope which comes as standard with the ElastoStart must be
  replaced by a 3 x 1060mm starter rope (1120 195 8200).

4.    Service Accessories

4.1   Special Servicing Tools
Special servicing tools are listed in the service manuals for the series 4140 powerhead and
STIHL 4140 power tool components.

4.2   Servicing Aids

Part Name                           Part No.              Application
Carburetor parts kit                1129 007 1062         Zama C1Q S49
Set of gaskets                      4228 007 1050         Engine
Lubricating grease                  0781 120 1111         Oil seals
- 225 g tube
Dirko sealant                       0783 830 2120         Engine pan/cylinder sealing faces
Electrician’s repair kit            5910 007 1050         Electrical system
Standard commercial solvent-                              Cleaning crankshaft stub
based degreaser containing no
chlorinated or hydrogenated
hydrocarbons

                                                                                          TI_44_1999_30_02.fm

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Technical Information 44.1999 Page 5

5. Repairs

If the unit is started up in the course of repairs or maintenance work, it is essential to strictly observe
all local and national safety regulations and the safety precautions outlined in the owner’s manual.

5.1 Carburetor Adjustment

Standard setting
. Check air filter and fit a new one if necessary
. Carefully screw down the idle speed screw (LD) counterclockwise (left-hand thread)
until it is against its seat, then open it two full turns clockwise.

Adjusting idle speed
. Carry out standard setting
. Start and warm up the engine

Engine stops while idling:
. Turn the idle speed screw (LD) slowly clockwise until engine runs smoothly - the cutting tool blades must
not move.

Cutting blades move while engine is idling:
. Turn the idle speed screw (LD) counterclockwise until the cutting blades stop moving and then turn the
screw about another full turn in the same direction (counterclockwise).

Erratic idling behavior, poor acceleration:
. Turn the idle speed screw (LD) slowly counterclockwise no more than 1/2 turn until engine runs smoothly.

5.2 Tightening Torques
Special servicing tools are listed in the service manuals for the series 4140 powerhead and
STIHL 4140 power tool components.

5.3 Service Note
The service manuals for the STIHL series 4140 powerhead and STIHL 4140 power tool components can be
used for servicing and repair procedures on model HS 45.
These service manuals do not include the chapters "Servicing the Carburetor", "Troubleshooting" or any repairs
involving standard procedures. Such procedures are described in separate handbooks, i.e. “Carburetors” and
"Standard Repairs, Troubleshooting".

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)m~ge 6 Technical Information 44.1999

5.4 Repair Times
The specified repair times assume that the work is Code Type of Repair HS 45
performed by trained personnel in a properly 1 Crankcase, Crankshaft, Crank 0.9
equipped service workshop. Bearings
2
The repair times are given in tenth of an hour 3 Crankcase Gasket/Sealing 0.8
(0.1 = 6 minutes). 4 Crankshaft Seals 0.9
(including pressure & vacuum test)
5 Cylinder and/or Piston 0.9
Note: This table for model HS 45 can be added to
6 Ignition Module 0.5
the STIHL repair times table manual.
7 Fule Hose 0.5
8 Replace Gear Box Cover 0.4
9 Repair/Rebuild Carburetor 0.8
10 Replace Carburetor, Carburetor 0.4
6. Spare Parts Jet (if tried to repair use code 9)
An illustrated parts list is available for the new 11 Throttle Handle, Throttle Control, 0.5
model. Cable
12 Recoil Starter 0.5
13 Cluch 0.5
14 Cutter Bar 0.5
15 Muffler 0.4
16 Air Filter, Filter Cover, Tank Cap, 0.3
Tank Vent, Fuel Filter, Spark Plug,
Misc. Minor Repairs
17 Stop Switch 0.4
18 Fuel Tank 0.4
19 Repair Gearbox, Gears/Bearings 0.8
20 All Other Repairs 0.5
✂

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