Technical Information · issue 7 of 1995
Flywheel; carburetor; wiring harness; front handle
Model 044 artic=ch~in=s~ws=from=m~chine=number=X 30 991 112=will=be=equipped=with=he~ted=h~ndles=in
Part changes (3)
| Was | Becomes | What the bulletin says |
|---|---|---|
| 1128 400 1205 | 1128 400 1213 | The original flywheel 1128 400 1205 will be replaced by the version 1128 400 1213. |
| 1128 430 0500 | 1128 430 0501 | The original thermostatic switch 1128 430 0500 will be replaced by the new version 1128 430 0501. |
| 1128 790 1705 | 1128 790 1707 | The original front handle 1128 790 1705 has been replaced by the new version 1128 790 1707. |
Full text
Page 1 of 6
Technical Information
07.95
STIHL 044 Arctic Chain Saws - Series 1128
&RQWHQWV
1. Flywheel (more powerful magnet)
2. Carburetor (heating element, thermostatic switch)
3. Wiring harness (wires for handle heating added)
4. Front handle, rear handle
(heating elements with higher resistance)
5. Circuit diagram
6. Routing the wires (in area of ignition
7.
module, in carburetor box)
Summary
8. Functional checks
Model 044 artic=chain saws from machine number X 30 991 112=will be equipped with heated handles in
addition to carburetor heating.
The electrical data of the carburetor heating system has been changed in this connection. The electrical data
of the handle heating system in this machine version differs from the electrical data of previous saws
equipped only with handle heating (044 W). The following components have been modified:
1.=====Flywheel
The original flywheel 1128 400 1205 will be
replaced by the version 1128 400 1213.
A more powerful permanent magnet is installed in
the flywheel. With the new flywheel the generator’s
output has been increased by up to 45% -
depending on RPM. Flywheels can be identified
by the size of the magnet. The original flywheel 11 6m
m m
1128 400 1205 must not be installed in machines 1/2 m 1/4
with carburetor and handle heating system " "
because the heat output would be unsatisfactory.
32TI001 KN
Left: Original flywheel 1128 400 1205
Right: New flywheel 1128 400 1213
)Technical Information 07.95 - Page 2
2.======Carburetor
The original `PjJp=23=carburetor will be replaced by
the `PjJp=24=carburetor. The differences between
the two carburetors are the heating element and
thermostatic switch.
2.1.====Heating element
The heating element bonded to the carburetor body
on the original version has been deleted. Instead,
the new heating element (2) -1128 434 5101- will be
installed between the baffle (1) and carburetor (3).
Resistances at a temperature of
+ 25 C =77F=.===================================================================P
Original heating element 4Ω 2
132TI002
New heating element 8Ω 1
1128 434 5101
Left: fo
Original carburetor with bonded heating
element
Right: New heating element between carburetor
2.2.====Thermostatic switch========================================~nd baffle
The original thermostatic switch 1128 430 0500 will
be replaced by the new version 1128 430 0501.
On the new version the switch cuts out the carbure-
tor heating system at a lower temperature. This
means that more power is available for the handle
heating system after a shorter period; the handles
therefore warm up faster.
Original New
version version
Cut-out +15 ... +21°C +5 ... +11°C
temperature (59 ... 70°F) (41 ... 52°F)
)Technical Information 07.95 - Page 3
3.=======Wiring harness
Wires for the handle heating system have
been added to the original wiring harness
1128 440 3007. The part number of the new wiring
harness is 1128 440 3012.
4.=======Front handle, rear handle
The original front handle 1128 790 1705 has been
replaced by the new version 1128 790 1707.
The heating element in the new front handle has a
higher electrical resistance.
The electrical resistance of the heating element
in the rear handle was also increased.
The new element 1128 434 5000 differs from the
original version in that it has thinner printed
conductors which run in wavy lines.
132TI003
The resistances in the following table refer to a
temperature of + 25C =77F=.==================================fo
Left: Original heating element 1125 434 5000
Right: New heating element 1128 434 5000
Original New
version version
Rear handle
element 0.225 ... 0.275 Ω 0.9 ... 1.1 Ω
Front handle
element 1.44 ...1.76 Ω 6.3 ... 7.7 W
Service notes
• If the new flywheel 1128 400 1213 is installed in a saw up to machine number X 30 991 111, the heating
element 1128 434 5000 must be bonded in the rear handle. Furthermore, the front handle 1128 790 1707
has to be fitted in place of the original front handle. The different front handles can be identified by the
resistance of the heating element - see table above.
A machine with the original front handle 1128 790 1705 and a new flywheel 1128 400 1213 must not
be run at full throttle for more than about 4 minutes at a time. The heating element would burn out if
the machine is run for a longer period at maximum engine speed.
• The original front handle 1128 790 1705 may only be fitted to saws up to machine number X 30 991 111.
)Technical Information 07.95 - Page 4
5.=Circuit diagram
2
3 6
1 Generator
2 Round connector 1 G 7 T
3 Heating element in rear 4
handle
4 Element in front handle
5 Heater switch 5
132TI004
6 Heating element on carb
7 Thermostatic switch
6.====Routing the wires
6.1===... in area of ignition module
The wire from the generator must be positioned
as follows after completing work in the area of the 1
ignition module: 3 2
• Push retainer (1) into crankcase recess.
• Turn round connector (2) to the position shown
in the illustration.
• Install the ignition module
132TI005
The wire must be loacted in the slot (3) in the
crankcase so that it is well clear of the flywheel.
6.2=... in carburetor box
6.2.1.=Wire under the thermostatic switch
Care must be taken not to bend or kink the plug
connector during installation or removal
since the connections might otherwise break.
132TI006
6.2.2.=Wires next to carburetor
The wires are laid in a loop, pushed through the
tube (1) -1121 442 0400- and positioned next to
the carburetor.
1
132TI007
)Technical Information 07.95 - Page 5
7.=Summary
Part Name Original New Key Rem. MOQ
version version H
Flywheel 1128 400 1205 1128 400 1213 1) 1
Carburetor C3M-S 23; 1128 120 0616 --- 2)
including items 1 and 2:
Carburetor C3M-S 24 --- 1128 120 0618 1
Screw M3 x 0.5 x 8 1128 122 7100 --- 1 2)
Contact 1128 431 7300 --- 2 2)
Heating element --- 1128 434 5101 1
Wiring harness 1128 440 3007 1128 440 3012 2) 1
Thermostatic switch 1128 430 0500 1128 430 0501 2) 1
Front handle 1128 790 1705 1128 790 1707 2)
Heating element 1125 434 5000 1128 434 5000 2)
Modification to be introduced from machine number X 30 991 112
5HPDUNV
1) Original version of part will be supplied from factory only as long as existing stocks last
2) Original version of part remains available for older machines
8. ====Functional checks
8.1.===Handle heating system
The testing procedures for the handle heating
system are described in detail in the 044 service
manual. However, the values for resistances and
temperatures given in this bulletin must be used.
8.2. =Carburetor heating
The carburetor heating system should be checked
if running problems occur while the engine is warm-
ing up, especially at outside temperatures below
freezing, or at idling speed and part-load RPM.
Poor idling behavior when the engine is warm is
also an indication of a fault in the carburetor
heating system.
The information necessary for checking the
carburetor heating system can be taken from the
following chart.
)Technical Information 07.95 - Page 6
Machine No. higher see TI 44.92
than X 30 991 111
yes
Check resistance of heating
element if
temperature = +25°C (77°F)
Resistance no
Fit new heating
approx.
8 Ohm?
foelement
yes
Check
thermostatic switch
Does switch close no
between +11 and +5°C Replace
(52 ... 41°F) ? thermostatic switch
yes
Does switch open no
between +5 and +11°C Replace
(41 ... 52°F)? thermostatic switch
yes
Carburetor heating
system in order
Waiblingen, January 2, 1995 Andreas Stihl
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