Technical Information · issue 4 of 2002
FS 45 C, FS 55 C, FS 55 TC: New Versions of Model
IssueTI 4/2002
Full text
Page 1 of 5
Technical Information
04.2002
New Versions of Model
FS 45 C, FS 46, FS 55 C, FS 55 TC Brushcutters – Series 4140
New Version of Model HL 45 C Hedge Trimmer – Series 4232
Contents
1. Catalytic Converter
2. Technical Description
2.1 Catalytic Converter
2.2 Heat Shield
2.3 Spacer
2.4 Maintenance and Repairs
2.5 Fuel
3. Service Notes
3.1 Heat Shield, Muffler with Heat Shield
3.2 Spacer
3.3 Routine Repairs
4. Repair Times
5. Spare Parts
1. Catalytic Converter 2. Technical Description
2
232TI004 KN
3
1
In some markets, the FS 45, FS 46, FS 55, FS 55 T
brushcutters and HL 45 hedge trimmer are now
available in a version with catalytic converter. The
new versions are identified by the suffix C in the
model designations.
232TI003 KN
With the exception of the muffler (1), heat shield (2),
spacer (3) and a thin flange (not shown) between
the cylinder and muffler, all parts are the same as
those of the latest production versions without a
catalytic converter.
TI_04_2002_02_01_01.fm english / USA
)m~ge 2 Technical Information 04.2002
2.1 Catalytic Converter
The catalyzer is a component which initiates
chemical reactions without being consumed in the
process. Integrated in the muffler, it is designed to
help reduce the amount of emissions in the exhaust
gas by way of a chemical reaction, which is initiated
by the catalyzer’s coating.
Description of Operation
232TI002 KN
A chemical reaction (afterburning) takes place when
294TI001 KN
exhaust gas flows through the catalyzer. Part of the
emissions is converted into water (H2O) and
carbon dioxide (CO2). The catalytic converter heats
This catalytic converter consists of the following
components: up to its normal and most efficient operating
temperature in this process.
. Honeycomb metal carrier with a catalytic
coating (precious metals) Hydrocarbon (HC) emissions are reduced in the
afterburning process.
. Stainless steel housing
232TI011 KN
The very hot exhaust gases flow through the duct on
the underside of the muffler where they are mixed
and cooled with fresh air.
TI_04_2002_02_01_01.fm Page 2 of 5
Technical Information 04.2002 Page 3
2.2 Heat Shield The spacer helps control the exit of the hot exhaust
gases.
It is mandatory that the spacer is always in place on
machines with a catalytic converter. Do not
remove!
2.4 Maintenance and Repairs
The catalytic converter is maintenance-free
providing the usual maintenance and care
232TI018 KN
instructions are observed. Repairs to the catalytic
converter are not possible.
The heat shield is wrapped around the muffler and
catalytic converter. It helps reduce thermal loads
and extends the exhaust port so that the housing is 2.5 Fuel
not damaged by the high exhaust gas temperatures. The two-stroke engine requires a mixture of
gasoline and engine oil.
The shape of the heat shield is critical for its correct
operation and must not be modified in any way. The quality of the fuels and lubricants and the mix
ratio have a critical influence on the operation and
life of the engine.
2.3 Spacer Gasoline
Use only brand-name gasoline with a minimum
octane rating of 89. Machines with a catalytic
converter must always be run on a mixture of
2-cycle engine oil and unleaded gasoline.
Engine Oil
STIHL recommends the use of STIHL 50:1 two-
stroke engine oil for the fuel mix in models with a
catalytic converter.
STIHL two-stroke engine oil features good
performance and reliability under high thermal loads
and helps reduce the build-up of deposits in the
catalytic converter. This aspect is very important to
ensure a long catalyst service life.
232TI010 KN
Very high exhaust gas temperatures are produced
in the afterburning process (see 2.1) in the catalytic
converter. For this reason a spacer is mounted to
the muffler outlet on machines with a catalytic
converter. The spacer helps reduce the risk of
combustible materials getting too close to the
exhaust gas outlet. At the same time, hot exhaust
gases in this area are mixed with cooler fresh air.
TI_04_2002_02_01_01.fm
)m~ge 4 Technical Information 04.2002
3. Service Notes 3.1.1 Installing Muffler with Heat Shield
3.1 Heat Shield, Muffler with Heat Shield
A B
232TI013 BL
232TI019 BL
The catalytic converter muffler comes pre-
assembled with the heat shield and screws. The
The heat shield is available as a separate item (A) screws are in the muffler.
and is also included with a replacement catalytic . Remove the parts from the box and do not
converter muffler (B). separate them
. Remove the starter housing
Important
When handling the heat shield make sure it is not
. fo
Remove the old muffler
damaged or distorted. It must not be stretched,
twisted, kinked, crushed or subjected to any other
mechanical stresses.
Do not install a damaged or distorted heat
shield.
The heat shield is important for correct exhaust gas
flow. The starter housing may be seriously damaged
if a faulty or distorted heat shield is installed.
232TI014 KN
Note on Installation:
It is not necessary to remove the main shroud to . Fit the new muffler with heat shield in position
remove and install the muffler and heat shield. The . Insert screws through the openings in the heat
screws are accessible through the openings in the shield and torque down (9 Nm / 6.6 lbf.ft)
shroud.
. Reinstall the starter housing
TI_04_2002_02_01_01.fm Page 3 of 5
Technical Information 04.2002 Page 5
3.1.2 Installing the Heat Shield
3.2 Spacer
If the spacer is damaged, it is essential to point out
to the user that it has to be replaced.
3.3 Routine Repairs
For servicing and repair procedures refer to the
service manuals for the series 4140 powerhead and
232TI015 BL
series 4140 machine components.
These service manuals do not include the chapters
"Servicing the Carburetor", "Troubleshooting" or any
. Carefully remove the heat shield from the box
repairs involving standard procedures. Such
without twisting or bending it
procedures are contained in the "Carburetors" and
. Remove the existing muffler "Standard Repairs, Troubleshooting" handbooks.
4. Repair Times
The existing repair times tables also apply to model
versions with a catalytic converter.
5. Spare Parts
232TI016 BL
The catalytic converter versions will be included in
the existing spare parts documentation.
. Fit existing screws in the muffler
232TI017 BL
. Attach the heat shield to the muffler
. Install the preassembled muffler as described
under 3.1.1
. Reinstall the starter housing
© 2002 Andreas Stihl AG & Co. Technical Documentation
Waiblingen D1/MTK-na 7543
TI_04_2002_02_01_01.fm Page 4 of 5
Page 5 of 5
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.