Technische Information
26.2001
Model HS 45 Hedge Trimmers – Series 4228
Contents
1. Gearbox (Gasket)
2. Handlebar with Hand Guard
3. Carburetor with LD Screw
(Flange and End Cover Mounting)
4. Model Update Package
4.1 Carburetor with 3 Adjusting Screws
4.2 Spacer Flange, Tensioner
4.3 Filter Housing (Choke Shutter), Filter Cover
4.4 Ignition Module, Crankshaft
4.5 Summary
1.
Gearbox (Gasket)
The previous gasket 4228 649 0300 (0.5 mm thick)
installed between the gearbox cover und gearbox
will be replaced by the new gasket 4228 649 0302
(0.75 mm thick).
253TI000 KN
Modification to be introduced – see Summary.
Summary
Item
1
1
Part Name
Previous
New
Remarks
Gasket (0.5 mm)
Gasket (0.75 mm)
4228 649 0300
---
--4228 649 0302
1)
Modification to be introduced – USA production: from serial number 2 51 134 557
Remarks
1) Previous version of part is no longer available from factory
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deutsch
Seite 2
2.
Technische Information 26.2001
Handlebar with Hand Guard
The previous handlebar (front handle) with hand
guard 4228 791 0100 will be replaced by a fully
interchangeable version 4228 791 0101 in order to
further optimize component strength.
Summary
Item
1
Part Name
Previous
New
Remarks
Handlebar with hand guard
4228 791 0100
4228 791 0101
1)
Remarks
1) Previous version of part is no longer available from factory
3.
Carburetor with LD Screw
(Flange and End Cover Mounting)
1
2
A new C1Q-S54 carburetor 4228 120 0601 is now
available. Four identical screws are now used to
secure the end cover and flange as an assembly –
instead of the previous separate arrangement with 2
short and 2 long screws.
1
2
The previous carburetor 4228 120 0600 has been
deleted.
3
4
5
6
6
7
7
Parts availability
253TI001 KN
3
Left: Carburetor 4228 120 0600
Right: Carburetor 4228 120 0601
The new versions of the end cover and flange can
only be used together. Use the new flange
4140 120 2250 for repairs to previous carburetors.
This replacement flange comes with the end cover,
gasket, metering diaphragm, 4 new mounting
screws and illustrated instructions.
The new flange and end cover are available as
separate items for repairs to the new version of the
carburetor.
TI_26_2001_02_01_01.fm
Technische Information 26.2001
Seite 3
Summary
Item
1
2
3
4
5
6
7
8
Part Name
Previous
New
Remarks
Carburetor C1Q-S49B;
including items 1 to 4, 6, 7:
Carburetor C1Q-S54;
including items 1, 2, 5 to 7:
Screw
End cover
Screw (2x)
Flange
Flange
Metering diaphragm
Gasket
Flange; including
items 1, 2, 5 to 7
4228 120 0600
---
1)
---
4228 120 0601
4226 122 7100
4226 121 0800
1128 122 7100
4226 120 2200
--4129 121 4700
1129 129 0900
---
4226 122 7100
4140 121 0800
----4140 120 2200
4129 121 4700
4129 129 0902
4140 120 2250
2)
3)
3)
3)
3)
4)
Remarks
1) Previous version of part is no longer available from factory
2) Quantity changed from 2 to 4
3) Previous version of part remains available for other models
4) Replacement part for carburetor 4228 120 0600
4.
Model Update Package
Modifications will come on line in the near future to further optimize functionality. The parts and assemblies
affected (carburetor with 3 adjusting screws, spacer flange, tensioner, filter housing, filter cover, ignition
module, crankshaft) are described in chapters 4.1. to 4.5.
4.1
Carburetor with 3 Adjusting Screws
The carburetor 4228 120 0601 discussed in chapter
3 (BIS* carburetor with LD screw) will be replaced
by the new version 4228 120 0603 (with H, L and LA
screws).
The new carburetor’s high speed screw is equipped
with a cap to limit its range of adjustment. The low
speed screw and idle speed screw are also
equipped with funnel-shaped caps to ease access
to the adjustment screws.
392TI033 KN
*BIS = Balanced Idle System
Left: Previous carburetor with LD screw
Right: New carburetor with H, L and LA screws
4.1.1 Construction
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Seite 4
Technische Information 26.2001
4.1.3 Repairs / servicing
1
4
2
.
Low speed screw (1)
.
High speed screw (2)
.
Limiter cap for high speed screw (3)
.
Stop pin (4)
392TI036 KN
392TI034 KN
3
The limiter cap has to be removed from the high
speed screw to replace a damaged high speed
screw or clean the carburetor.
.
Use suitable pliers to pull off the cap.
Do not re-use caps because they may be damaged
during removal.
4.1.4 Adjustment after repairs / servicing
Check the air filter and clean or replace as
necessary.
.
Check spark arresting screen and clean or
replace as necessary.
295TI012 KN
.
The cap is pushed over the knurled head of the
adjusting screw. The stop pin (see arrow) in the
carburetor body serves to limit adjustment.
4.1.5 Standard setting of H screw
(without cap)
4.1.2 Function
392TI037 KN
H
392TI035 KN
270°
.
Starting with the screw lightly against its seat:
Open high speed screw (H) 1 1/2 turns.
The pin limits rotation of the cap and thus the
range of adjustment of the high speed screw to
270 degrees (3/4 turn).
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Technische Information 26.2001
Seite 5
4.1.9 Setting instructions for users
4.1.6 Installing the cap
The user may adjust the carburetor’s high speed
screw within a range of 270 degrees.
This enables the user to make the mixture leaner if
necessary, e.g. for operation at high altitude.
H
392TI038 KN
The procedure for setting the new carburetor is as
described in the owner’s manual (see chapter
"Adjusting the Carburetor").
Caps that have been removed once must not be
re-used because they might be damaged.
.
Position new cap for high speed screw (H) so
that it is in line with "rich" stop (arrow).
.
Push cap home as far as stop against
carburetor body.
4.2
Spacer Flange, Tensioner
The previous spacer flange 4140 121 1600 will be
replaced by the new version 4140 121 1605 when
the new carburetor is introduced (chapter 4.1). The
surface structure of the new spacer flange has been
designed for optimized fuel/air intake flow.
253TI002 KN
4.1.7 Adjusting idle speed
L
Tensioner 4140 182 7600 (with pin and
push nut)
Right: Tensioner 4140 182 7602
LA
295TI017 KN
Left:
Starting with the screws lightly against their seats:
.
Open low speed screw (L) one full turn
counterclockwise.
.
Use idle speed screw (LA) to set engine speed
to 2,800 RPM.
This adjustment must be checked with a
tachometer.
4.1.8 Checking running behavior
.
Open the throttle several times to check that
engine accelerates smoothly.
Engine must run smoothly at idle speed.
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The previous tensioner 4140 182 7600 will be
replaced by tensioner 4140 182 7602. The new
tensioner runs on the spacer flange’s integral pivot
pin (see arrow). Therefore, the bearing pin
4137 123 8900 and push nut 9417 003 7512 are no
longer required and have been deleted.
Seite 6
4.3
Technische Information 26.2001
4.4
Filter Housing (Choke Shutter), Filter
Cover
Ignition Module, Crankshaft
Modified versions of the filter housing, choke shutter
and the filter cover will be installed at the same time
as the new carburetor described in chapter 4.1.
L
1
253TI004 KN
H
3/4
253TI003 KN
LD
The positon of the hinge on the filter housing and
filter cover has been moved (see arrows) to allow
access to the adjusting screws of the new
carburetor. The symbols for setting the new
carburetor are marked on the new filter cover. In
addition, a modified choke shutter has been
installed.
Parts availability
Filter cover 4228 141 0500 remains available as a
spare for HS 45 machines with carburetor
4228 120 0600 / 0601 (BIS carburetor with LD
screw).
Position of slot for flywheel
Left: Crankshaft 4228 030 0400
Right: Crankshaft 4228 030 0402
Ignition timing and cut-off speed range have been
optimized. For this reason the previous ignition
module 4140 400 1300 has been replaced by
ignition module 4140 400 1302 and a new
crankshaft. Compared with the previous version, the
position of the key slot for the flywheel has been
changed on the new crankshaft 4228 030 0402 (see
arrows).
Service note
In case of a repair, only the new versions of the parts
may be used for HS 45 machines with carburetor
4228 120 0603.
The new filter housing 4228 140 2850 must be used
as a replacement for all HS 45 machines –
irrespective of the carburetor version. The
replacement part includes the filter and prefilter as
well as the new replacement filter cover
4228 141 0502. Since there are no setting symbols
on this filter cover, it can be used as a universal
replacement.
The modified choke shutter is made from orangecolored plastic so that it can be easily distinguished
from the previous choke shutter (black).
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Technische Information 26.2001
4.5
Item
Seite 7
Summary
Part Name
Previous
New
Remarks
1
2
Carburetor C1Q-S54
Carburetor C1Q-S67
4228 120 0601
---
--4228 120 0603
1)
2)
3
4
5
6
7
4140 121 1600
4140 182 7600
4137 123 8900
9417 003 7512
---
4140 121 1605
4140 182 7602
----4228 140 2850
1)
3)
1)
1)
4)
4140 140 2800
-*-
5) 6)
9
10
11
12
13
14
Spacer flange
Tensioner
Pin
Push nut
Filter housing;
including items 8 to 14:
Filter housing;
including items 9 to 11:
Lever
Choke shutter
Push nut
Filter
Prefilter
Filter cover
4140 141 3700
4140 141 3800
9417 003 7512
4140 124 2800
4228 124 1500
4228 141 0500
4140 141 3700
4140 141 3801
9417 003 7512
4140 124 2800
4228 124 1500
4228 141 0502
15
16
Crankshaft
Ignition module
4228 030 0400
4140 400 1300
4228 030 0402
4140 400 1302
8
1)
1)
1)
1)
Modification to be introduced: in progress
Remarks
1) Previous version of part remains available as spare for older machines
2) For component parts see illustrated parts list
3) Previous version of part will be supplied from factory only as long as existing stocks last
4) Use part as replacement for previous and new versions of filter housing
5) Previous version of part will not be available when modification is introduced
6) New version of part not available as separate item (use item 7 as replacement)
Last Technical Information on model HS 45: 44.1999
© 2001 Andreas Stihl AG & Co.
Waiblingen
TI_26_2001_02_01_01.fm
Technical Documentation
D1/MTK-sc
7317