STIHL KM 55 R Owner's Manual
STIHL KM 55 R
Warning!
Read and follow all safety
precautions in Instruction Manual –
improper use can cause serious or
fatal injury.
Advertencia!
Lea y siga todas las precauciones
de seguridad dadas en el manual
de instrucciones – el uso incorrecto
puede causar lesiones graves o
mortales.
{
Instruction Manual
Manual de instrucciones
Instruction Manual
1 - 29
Manual de
instrucciones
31 - 63
Contents
English
KombiSystem 2
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 3
Approved KombiTools 10
Mounting the Loop Handle 11
Fuel 12
Fueling 13
Original Instruction ManualPrinted on chlorine-free paper
Starting / Stopping the Engine 13
Operating Instructions 15
Cleaning the Air Filter 16
Engine Management 16
Adjusting the Carburetor 17
Spark Plug 18
Engine Running Behavior 19
Rewind Starter 20
Storing the Machine 20
Inspections and Maintenance by
Dealer 20
Maintenance and Care 21
Main Parts 22
Specifications 23
Printing inks contain vegetable oils, paper can be recycled.
Special Accessories 24
Maintenance and Repairs 24
STIHL Incorporated Federal
Emission Control Warranty
Statement 25
STIHL Incorporated California
Exhaust and Evaporative
Emissions Control Warranty
Statement 27
Trademarks 29
Allow only persons who fully understand
the manuals of the KombiEngine and the
KombiTool to operate this power tool
combination.
To receive maximum performance and
satisfaction from your STIHL power tool,
it is important that you read, understand
and follow the safety precautions and
the operating and maintenance
instructions in chapter "Safety
Precautions and Working Techniques"
before using your power tool. For further
information you can go to
www.stihlusa.com.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in the
two manuals.
Warning!
Because this KombiEngine is the
engine for a high-speed power tool,
some special safety precautions must
be observed to reduce the risk of personal injury. Careless or improper use
may cause serious or even fatal injury.
{
© ANDREAS STIHL AG & Co. KG, 2011
0458-461-8621-A. M9.A11.PM.
0000001986_003_GB
KM 55 R, KM 55 RC
1
English
.
.
.
.
002BA442 KN
+
+
KombiSystem
In the STIHL KombiSystem a number of
different KombiEngines and KombiTools
can be combined to produce a power
tool. In this instruction manual the
functional unit formed by the
KombiEngine and KombiTools is
referred to as the power tool.
Therefore, the separate instruction
manuals for the KombiEngine and
KombiTool should be used together for
the power tool.
Always read and and make sure you
understand both instruction manuals
before using your power tool for the first
time and keep them in a safe place for
future reference.
Guide to Using this Manual
Pictograms
All the pictograms attached to or
embossed on the machine are shown
and explained in this manual.
Symbols in Text
Many operating and safety instructions
are supported by illustrations.
The individual steps or procedures
described in the manual may be marked
in different ways:
N A bullet marks a step or procedure.
A description of a step or procedure that
refers directly to an illustration may
contain item numbers that appear in the
illustration. Example:
N Loosen the screw (1).
N Lever (2) ...
In addition to the operating instructions,
this manual may contain paragraphs
that require your special attention. Such
paragraphs are marked with the
symbols and signal words described
below:
Danger!
Indicates an imminent risk of severe or
fatal injury.
Warning!
Indicates a hazardous situation which, if
not avoided, could result in severe or
fatal injury.
Caution!
Indicates a risk of property damage,
including damage to the machine or its
individual components.
Engineering Improvements
STIHL’s philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements
are made from time to time. Therefore,
some changes, modifications and
improvements may not be covered in
this manual. If the operating
characteristics or the appearance of
your machine differ from those
described in this manual, please contact
your STIHL dealer for assistance.
2
KM 55 R, KM 55 RC
English
Safety Precautions and
Working Techniques
Because this KombiEngine is the engine for a
high-speed power tool,
special safety precautions must be observed to
reduce the risk of personal injury.
It is important that you
read, fully understand
and observe the following
safety precautions and
warnings. Read the
instruction manuals and
the safety precautions of
your KombiEngine and
KombiTool periodically.
Careless or improper use
may cause serious or
fatal injury.
Have your STIHL dealer show you how
to operate your power tool. Observe all
applicable local safety regulations,
standards and ordinances.
Warning!
Do not lend or rent your power tool without the instruction manuals. Be sure that
anyone using it understands the information contained in these manuals.
Use your power tool only for the
applications described in the instruction
manual of the KombiTool you are using.
Warning!
Do not use it for other purposes, since
misuse may result in personal injury or
property damage, including damage to
the machine.
Warning!
Minors should never be allowed to use
this power tool. Bystanders, especially
children, and animals should not be
allowed in the area where it is in use.
Warning!
To reduce the risk of injury to bystanders and damage to property, never let
your power tool run unattended. When it
is not in use (e.g. during a work break),
shut it off and make sure that unauthorized persons do not use it.
Most of these safety precautions and
warnings apply to the use of all STIHL
power tools. Different models may have
different parts and controls. See the
appropriate section of your
KombiEngine and KombiTool instruction
manuals for a description of the controls
and the function of the parts of your
model.
Do not clean your machine with a
pressure washer. The solid jet of water
may damage parts of the machine.
Safe use of a KombiEngine involves
1. the operator
2. the power tool
3. the use of the power tool
THE OPERATOR
Physical Condition
You must be in good physical condition
and mental health and not under the
influence of any substance (drugs,
alcohol, etc.) which might impair vision,
dexterity or judgment. Do not operate
this machine when you are fatigued.
Warning!
Be alert – if you get tired, take a break.
Tiredness may result in loss of control.
Working with any power tool can be
strenuous. If you have any condition
that might be aggravated by strenuous
work, check with your doctor before
operating this machine.
Warning!
Prolonged use of a power tool (or other
machines) exposing the operator to
vibrations may produce whitefinger disease (Raynaud's phenomenon) or
carpal tunnel syndrome.
These conditions reduce the hand's
ability to feel and regulate temperature,
produce numbness and burning
sensations and may cause nerve and
circulation damage and tissue necrosis.
All factors which contribute to
whitefinger disease are not known, but
cold weather, smoking and diseases or
physical conditions that affect blood
vessels and blood transport, as well as
high vibration levels and long periods of
exposure to vibration are mentioned as
factors in the development of whitefinger
KM 55 R, KM 55 RC
3
English
disease. In order to reduce the risk of
whitefinger disease and carpal tunnel
syndrome, please note the following:
– Most STIHL power tools are
available with an anti-vibration
("AV") system designed to reduce
the transmission of vibrations
created by the machine to the
operator's hands. An AV system is
recommended for those persons
using power tools on a regular or
sustained basis.
– Wear gloves – not while using
KombiTool BG-KM – and keep your
hands warm.
– Keep the AV system well
maintained. A power tool with loose
components or with damaged or
worn AV elements will tend to have
higher vibration levels.
– Maintain a firm grip at all times, but
do not squeeze the handles with
constant, excessive pressure. Take
frequent breaks.
All the above-mentioned precautions do
not guarantee that you will not sustain
whitefinger disease or carpal tunnel
syndrome. Therefore, continual and
regular users should closely monitor the
condition of their hands and fingers. If
any of the above symptoms appear,
seek medical advice immediately.
Warning!
The ignition system of the STIHL unit
produces an electromagnetic field of a
very low intensity. This field may interfere with some pacemakers. To reduce
the risk of serious or fatal injury, persons
with a pacemaker should consult their
physician and the pacemaker manufacturer before operating this tool.
Proper Clothing
Warning!
To reduce the risk of injury, the operator
should wear proper protective apparel.
Warning!
Power tool noise may
damage your hearing.
Wear sound barriers (ear
plugs or ear mufflers) to
protect your hearing.
Continual and regular
users should have their hearing
checked regularly.
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
For further instructions on proper
clothing see the safety precautions in
the instruction manual of the KombiTool
you are using.
THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
"Main Parts and Controls."
Warning!
Never modify this power tool in any way.
Only attachments supplied by STIHL or
expressly approved by STIHL for use
with the specific STIHL KombiEngine
model are authorized. Although certain
unauthorized attachments are useable
with STIHL power tools, their use may,
in fact, be extremely dangerous.
If this tool is subjected to unusually high
loads for which it was not designed (e.g.
heavy impact or a fall), always check
that it is in good condition before
continuing work. Check in particular that
the fuel system is tight (no leaks) and
that the controls and safety devices are
working properly. Do not continue
operating this machine if it is damaged.
In case of doubt, have it checked by your
STIHL servicing dealer.
THE USE OF THE POWER TOOL
Transporting the Power Tool
Warning!
Always switch off the engine and make
sure the working tool has stopped
before putting a power tool down. When
transporting your power tool in a vehicle, properly secure it to prevent
turnover, fuel spillage and damage to
the power tool.
4
KM 55 R, KM 55 RC
English
001BA220 KN
Fuel
Your STIHL power tool uses an oilgasoline mixture for fuel (see the
chapter on "Fuel" of your instruction
manual).
Warning!
Gasoline is an extremely
flammable fuel. If spilled
and ignited by a spark or
other ignition source, it
can cause fire and seri-
ous burn injury or
property damage. Use extreme caution
when handling gasoline or fuel mix. Do
not smoke or bring any fire or flame near
the fuel or the power tool. Note that
combustible fuel vapor may escape
from the fuel system.
Fueling Instructions
Warning!
To reduce the risk of serious injury from
burns, never attempt to refuel the unit
until it has been completely removed
from the operator.
Warning!
Fuel your power tool in well-ventilated
areas, outdoors. Always shut off the
engine and allow it to cool before refueling. Gasoline vapor pressure may
build up inside the fuel tank depending
on the fuel used, the weather conditions
and the tank venting system.
In order to reduce the risk of burns and
other personal injury from escaping gas
vapor and fumes, remove the fuel filler
cap on your power tool carefully so as to
allow any pressure build-up in the tank
to release slowly. Never remove the fuel
filler cap while the engine is running.
Select bare ground for fueling and move
at least 10 feet (3 m) from the fueling
spot before starting the engine. Wipe off
any spilled fuel before starting your
machine.
Warning!
Check for fuel leakage
while refueling and during operation. If fuel
leakage is found, do not
start or run the engine
until the leak is fixed and
any spilled fuel has been wiped away.
Take care not to get fuel on your clothing. If this happens, change your
clothing immediately.
Different models may be equipped with
different fuel caps.
Toolless cap with grip
Warning!
In order to reduce the risk of fuel spillage and fire from an improperly
tightened fuel cap, correctly position
and tighten the fuel cap in the fuel tank
opening.
To do this with this STIHL cap, raise the
grip on the top of the cap until it is upright
at a 90° angle. Insert the cap in the fuel
tank opening with the raised positioning
marks on the grip of the cap and on the
fuel tank opening lining up. Using the
grip, press the cap down firmly while
turning it clockwise as far as it will go
(approx. 1/4 turn).
Fold the grip flush with
the top of the cap. Grip
the cap and check for
tightness. If the grip does
not lie completely flush
with the cap and the
detent on the grip does
not fit in the corresponding recess in the filler
opening, or if the cap is
loose in the filler opening,
the cap is not properly
seated and tightened and
you must repeat the
above steps.
Misaligned, damaged or broken cap
N If the cap does not drop fully into the
opening when the positioning marks
line up and/or if the cap does not
tighten properly when twisted, the
base of the cap may be prematurely
rotated (in relation to the top) to the
closed position. Such misalignment
KM 55 R, KM 55 RC
5
English
001BA227 KN
001BA226 KN
can result from handling, cleaning
or an improper attempt at
tightening.
Left: Base of cap in closed posi-
tion (with open space)
Right: Base of cap correctly posi-
tioned for installation
N To return the cap to the open
position for installation, turn the cap
(with the grip up) until it drops fully
into the tank opening. Next, twist the
cap counterclockwise as far as it will
go (approx. 1/4 turn) – this will twist
the base of the cap into the correct
position. Then, twist the cap
clockwise, closing it normally.
N If your cap still does not tighten
properly, it may be damaged or
broken; immediately stop use of the
unit and take it to your authorized
STIHL dealer for repair.
Screw Cap
Warning!
Unit vibrations can cause
an improperly tightened
fuel filler cap to loosen or
come off and spill quantities of fuel. In order to
reduce the risk of fuel
spillage and fire, tighten the fuel filler
cap by hand as securely as possible.
See also the "Fueling" chapter in your
Instruction Manual for additional
information.
Before Starting
Warning!
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger lockout, stop switch, cutting
attachment, deflector and harness. The
throttle trigger must move freely and
always spring back to the idle position.
Never attempt to modify the controls or
safety devices.
Warning!
Never operate your power tool if it is
damaged, improperly adjusted or maintained, or not completely or securely
assembled.
Warning!
Check that the spark plug boot is
securely mounted on the spark plug – a
loose boot may cause arcing that could
ignite combustible fumes and cause a
fire.
Keep the handles clean and dry at all
times; it is particularly important to keep
them free of moisture, pitch, oil, fuel mix,
grease or resin in order for you to
maintain a firm grip and properly control
your power tool.
Starting
Start the engine at least 10 feet (3 m)
from the fueling spot, outdoors only.
For specific starting instructions, see the
appropriate section of your
KombiEngine and KombiTool manuals.
Place the power tool on firm ground or
other solid surface in an open area.
Maintain good balance and secure
footing.
Warning!
To reduce the risk of injury from loss of
control, be absolutely sure that the
working tool is clear of you and all other
obstructions and objects, including the
ground, because when the engine starts
at starting-throttle, engine speed will be
fast enough for the clutch to engage and
move the working tool.
Once the engine has started,
immediately blip the throttle trigger,
which should release the starting throttle
and allow the engine to slow down to
idle.
6
KM 55 R, KM 55 RC
Warning!
002BA057 KN
Your power tool is a one-person
machine. Do not allow other persons in
the general work area, even when
starting.
Warning!
To reduce the risk of injury from loss of
control, do not attempt to "drop start"
your power tool.
Warning!
When you pull the starter grip, do not
wrap the starter rope around your hand.
Do not let the grip snap back, but guide
the starter rope to rewind it properly.
Failure to follow this procedure may
result in injury to your hand or fingers
and may damage the starter
mechanism.
See also the safety precautions on
Starting in the instruction manual of the
KombiTool.
Important Adjustments
Warning!
To reduce the risk of personal injury
from loss of control or contact with the
running working tool, do not use a
power tool with incorrect idle adjustment. At correct idle speed, the working
tool should not move. For directions on
how to adjust idle speed, see the appropriate section of your instruction
manual.
If you cannot set the correct idle speed,
have your STIHL dealer check your
power tool and make proper
adjustments and repairs.
During Operation
Holding and Controlling the Power
Tool
Always hold the unit firmly with both
hands on the handles while you are
working. Wrap your fingers and thumbs
around the handles.
Your right hand should grip the rear
handle. This also applies to left-handers.
Warning!
To reduce the risk of injury from loss of
control, never work on a ladder or on
any other insecure support.
Working Conditions
Operate and start your power tool only
outdoors in a well ventilated area.
Operate it under good visibility and
daylight conditions only. Work carefully.
English
Warning!
As soon as the engine is
running, this product generates toxic exhaust
fumes containing chemicals, such as unburned
hydrocarbons (including
benzene) and carbon monoxide, that
are known to cause respiratory problems, cancer, birth defects, or other
reproductive harm. Some of the gases
(e.g. carbon monoxide) may be colorless and odorless. To reduce the risk of
serious or fatal injury/illness from inhaling toxic fumes, never run the machine
indoors or in poorly ventilated locations.
KM 55 R, KM 55 RC
7
English
Warning!
Inhalation of certain dusts, especially
organic dusts such as mold or pollen,
can cause susceptible persons to have
an allergic or asthmatic reaction. Substantial or repeated inhalation of dust
and other airborne contaminants, in particular those with a smaller particle size,
may cause respiratory or other illnesses. Control dust at the source
where possible. Use good work practices, such as operating the unit so that
the wind or operating process directs
any dust raised by the power tool away
from the operator. Follow the recommendations of EPA/OSHA/NIOSH and
occupational and trade associations
with respect to dust ("particulate matter"). When the inhalation of dust cannot
be substantially controlled, i.e., kept at
or near the ambient (background) level,
the operator and any bystanders should
wear a respirator approved by
NIOSH/MSHA for the type of dust
encountered.
Operating Instructions
Warning!
Do not operate your power tool using
the starting throttle lock, as you do not
have control of the engine speed.
In the event of an emergency, switch off
the engine immediately – move the slide
control / stop switch to 0 or STOP.
Warning!
The muffler and other parts of the
engine (e.g. fins of the cylinder, spark
plug) become hot during operation and
remain hot for a while after stopping the
engine. To reduce risk of burns do not
touch the muffler and other parts while
they are hot.
Warning!
To reduce the risk of fire and burn injury,
keep the area around the muffler clean.
Remove excess lubricant and all debris
such as pine needles, branches or
leaves. Let the engine cool down sitting
on concrete, metal, bare ground or solid
wood away from any combustible
substances.
Warning!
Never modify your muffler. The muffler
could be damaged and cause an
increase in heat radiation or sparks,
thereby increasing the risk of fire and
burn injury. You may also permanently
damage the engine. Have your muffler
serviced and repaired by your STIHL
servicing dealer only.
Catalytic Converter
Warning!
Some STIHL power tools
are equipped with a cata-
lytic converter, which is
designed to reduce the
exhaust emissions of the
engine by a chemical
process in the muffler. Due to this process, the muffler does not cool down as
rapidly as conventional mufflers when
the engine returns to idle or is shut off.
To reduce the risk of fire and burn injuries, the following specific safety
precautions must be observed.
Warning!
Since a muffler with a catalytic converter
cools down less rapidly than conventional mufflers, always set your power
tool down in the upright position and
never locate it where the muffler is near
dry brush, grass, wood chips or other
combustible materials while it is still hot.
Warning!
An improperly mounted or damaged cylinder housing or a damaged/deformed
muffler shell may interfere with the cooling process of the catalytic converter.
To reduce the risk of fire or burn injury,
do not continue work with a damaged or
improperly mounted cylinder housing or
a damaged/deformed muffler shell.
Your catalytic converter is furnished with
screens designed to reduce the risk of
fire from the emission of hot particles.
Due to the heat from the catalytic
reaction, these screens will normally
8
KM 55 R, KM 55 RC
stay clean and need no service or
maintenance. If you experience loss of
performance and you suspect a clogged
screen, have your muffler maintained by
a STIHL servicing dealer.
MAINTENANCE, REPAIR AND
STORING
Maintenance, replacement, or repair
of the emission control devices and
systems may be performed by any
nonroad engine repair establishment
or individual. However, if you make a
warranty claim for a component
which has not been serviced or
maintained properly or if
nonapproved replacement parts were
used, STIHL may deny coverage.
Warning!
Use only identical STIHL replacement
parts for maintenance and repair. Use of
non-STIHL parts may cause serious or
fatal injury.
Strictly follow the maintenance and
repair instructions in the appropriate
section of your KombiEngine and
KombiTool instruction manuals. Please
refer to the maintenance charts
respectively the maintenance notes in
these manuals.
Warning!
Always stop the engine and make sure
that the working tool is stopped before
doing any maintenance or repair work or
cleaning the power tool. Do not attempt
any maintenance or repair work not
described in your KombiEngine and
KombiTool instruction manuals. Have
such work performed by your STIHL
servicing dealer only.
Warning!
Use the specified spark plug and make
sure it and the ignition lead are always
clean and in good condition. Always
press spark plug boot snugly onto spark
plug terminal of the proper size. (Note: If
terminal has detachable SAE adapter
nut, it must be attached.) A loose connection between spark plug boot and
the ignition wire connector in the boot
may create arcing that could ignite combustible fumes and cause a fire.
Warning!
Never test the ignition system with the
ignition wire boot removed from the
spark plug or with a removed spark
plug, since uncontained sparking may
cause a fire.
English
Warning!
Do not operate your power tool if the
muffler is damaged, missing or modified. An improperly maintained muffler
will increase the risk of fire and hearing
loss. If your muffler was equipped with a
spark-arresting screen to reduce the
risk of fire, never operate your power
tool if the screen is missing or damaged.
Remember that the risk of forest fires is
greater in hot or dry weather.
Store the power tool in a dry and high or
locked location out of reach of children.
Before storing for longer than a few
days, always empty the fuel tank. See
chapter "Storing the machine" in this
manual.
KM 55 R, KM 55 RC
9
English
HT-KM
BF-KM
470BA018 KN
FCS-KM
FCB-KM
KW-KM
KB-KM
FH-KM
FS-KM
FS-KM
FSB-KM
BG-KM
Approved KombiTools
The following STIHL KombiTools may
be mounted on the KombiEngine:
KombiTool Purpose
FS-KM Brushcutter with
mowing head
FS-KM Brushcutter with
grass cutting blade
FSB-KM Brushcutter with
mowing head
HL-KM 135° Hedge trimmer,
adjustable
HL-KM 0° Hedge trimmer
FH-KM 135° Power scythe
BG-KM Blower
HT-KM Pole pruner
BF-KM Pick tines
FCB-KM Power edger
FCS-KM Power edger
KB-KM Bristle brush
KW-KM PowerSweep
The barrier bar supplied with the
machine must be mounted to the loop
handle – see also "Mounting the Loop
Handle".
10
KM 55 R, KM 55 RC
Mounting the Loop Handle
2
002BA098 KN
1
1
5
4
002BA099 KN
2
3
6
7
A
9
8
4
002BA353 KN
A barrier bar is supplied with the
machine. Attach the barrier bar to the
loop handle.
English
N Insert square nuts (1) in the barrier
bar (2) – the holes must line up
KM 55 R, KM 55 RC
N Insert the clamp (3) in the loop
handle (4) and position them
together on the shaft (5)
N Position clamp (6)
N Position barrier bar (2) – note
position!
N Line up the holes
N Insert bolts (7) in the holes – and
screw them into the barrier bar as
far as possible
N Fit the loop handle (4) at a distance
of (A) approx. 20 cm (8 in) forward
of the control handle (8)
N Orient the loop handle
N Tighten the bolts – lock the nuts if
necessary
The sleeve (9) is present depending on
the country and must be located
between the loop handle and control
handle.
Always leave the barrier bar attached.
11
English
Fuel
This engine is certified to operate on
unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of highquality gasoline and quality two-stroke
air cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 (R+M/2). If
the octane rating of the mid-grade
gasoline in your area is lower, use
premium unleaded fuel.
Fuel with a lower octane rating may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.
The chemical composition of the fuel is
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or even
damage the engine. For this reason
STIHL recommends that you use only
high-quality unleaded gasoline!
Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
with a manually adjustable carburetor
and should not be used in such engines.
Engines equipped with M-Tronic can be
run on gasoline with an ethanol content
of up to 25% (E25).
Use only STIHL two-stroke engine oil or
equivalent high-quality two-stroke
engine oils that are designed for use
only in air cooled two-cycle engines.
We recommend STIHL HP Ultra 2-Cycle
Engine Oil since it is specially
formulated for use in STIHL engines.
Do not use BIA or TCW rated (twostroke water cooled) mix oils or other
mix oils that state they are for use in both
water cooled and air cooled engines
(e.g., outboard motors, snowmobiles,
chain saws, mopeds, etc.).
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the canister from
your vehicle and place the canister on
the ground before filling. Do not fill fuel
canisters that are sitting in or on a
vehicle.
The canister should be kept tightly
closed in order to avoid any moisture
getting into the mixture.
The machine‘s fuel tank and the canister
in which fuel mix is stored should be
cleaned as necessary.
Fuel mix ages
Only mix sufficient fuel for a few days
work, not to exceed 3 months of storage.
Store in approved fuel-canisters only.
When mixing, pour oil into the canister
first, and then add gasoline. Close the
canister and shake it vigorously by hand
to ensure proper mixing of the oil with
the fuel.
Gasoline
US gal. US fl.oz
12.6
2 1/2 6.4
5 12.8
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
Oil (STIHL 50:1 or equivalent high-quality oils)
12
KM 55 R, KM 55 RC
English
232BA046 KN
2
233BA048 KN
1
6
7
5
4
3
233BA049 KN
4
Fueling
Before fueling, clean the filler cap and
the area around it to ensure that no dirt
falls into the tank.
Always thoroughly shake the mixture in
the canister before fueling your
machine.
In order to reduce the risk of burns
or other personal injury from
escaping gas vapor and fumes,
remove the fuel filler cap carefully
so as to allow any pressure buildup in the tank to release slowly.
After fueling, tighten fuel cap as
securely as possible by hand.
Starting / Stopping the
Engine
Controls
1 Stop switch
2 Throttle trigger lockout
3 Throttle lever
4 Tongue of throttle trigger
5 Catch
Positions of stop switch
6I – normal run position – the engine
is running or can start
70 – engine off – the ignition is
switched off
Starting
N Move the stop switch to I.
N Press down the throttle trigger
lockout and hold it there.
N Squeeze the throttle trigger until the
catch on the tongue (4) can be
engaged on the housing.
N Now release the throttle trigger,
tongue and trigger lockout in that
order. This is the starting throttle
position.
KM 55 R, KM 55 RC
13
English
9
8
232BA011 KN
232BA012 KN
233BA014 KN
232BA014 KN
Starting
N Set the choke lever (8) to
g if the engine is cold
e for warm start – also use this posi-
tion if the engine has been running
but is still cold.
N Press the fuel pump bulb (9) at least
five times – even if the bulb is
already filled with fuel.
14
N Place the unit on the ground: Check
that the working tool is not touching
the ground or any other obstacles –
see also "Starting / Stopping the
Engine" in the KombiTool
instruction manual.
N Make sure you have a safe and
secure footing.
N Hold the unit with your left hand and
press it down firmly – your thumb
should be under the fan housing.
Do not stand or kneel on the drive
tube.
N Hold the starter grip with your right
hand.
Version without Easy2Start
N Pull the starter grip slowly until you
feel it engage and then give it a brisk
strong pull.
Do not pull out the starter rope all
the way – it might otherwise
break.
Version with Easy2Start
N Pull the starter grip slowly until you
feel it engage and then pull it out
slowly and steadily.
Do not pull out the starter rope all
the way – it might otherwise
break.
KM 55 R, KM 55 RC
English
8
232TI015 KN
Both versions
N Do not let the starter grip snap back.
Guide it slowly back into the housing
so that the starter rope can rewind
properly.
N Crank the engine until it fires – after
no more than five pulls, move the
choke lever (8) to e.
N Continue cranking.
As soon as the engine runs
N Squeeze the throttle trigger to
disengage the tongue – the engine
will settle down to idle speed.
Your machine is now ready for
operation.
Make sure the carburetor is
correctly adjusted. The working
tool must not move when the
engine is idling.
Stopping the engine
N Move the stop switch to 0.
If the engine does not start
N Set the choke lever to
N Set the stop switch, lockout lever
and throttle trigger to the starting
throttle position.
N Start the engine by pulling the
starter rope briskly – 10 to 20 pulls
may be necessary.
If the engine still does not start
N Move the stop switch to 0.
N Remove the spark plug – see
"Spark Plug".
N Dry the spark plug.
N Crank the engine several times with
the starter to clear the combustion
chamber.
N Refit the spark plug – see "Spark
Plug".
N Move the stop switch to I.
N Set the choke lever to e – even if
the engine is cold.
N Now start the engine.
Fuel tank run until completely dry
N After refueling, press the fuel pump
bulb at least five times – even if the
bulb is filled with fuel.
N Start the engine.
e .
Operating Instructions
During break-in period
A factory-new machine should not be
run at high revs (full throttle off load) for
the first three tank fillings. This avoids
unnecessary high loads during the
break-in period. As all moving parts
have to bed in during the break-in
period, the frictional resistances in the
engine are greater during this period.
The engine develops its maximum
power after about 5 to 15 tank fillings.
During Operation
After a long period of full throttle
operation, allow the engine to run for a
short while at idle speed so that engine
heat can be dissipated by the flow of
cooling air. This protects enginemounted components (ignition,
carburetor) from thermal overload.
After Finishing Work
Storing for a short period: Wait for the
engine to cool down. Empty the fuel tank
and keep the machine in a dry place,
well away from sources of ignition, until
you need it again. For longer out-ofservice perionds – see "Storing the
Machine".
If you did not move the choke lever to e
quickly enough after the engine began to
fire, the combustion chamber is flooded.
KM 55 R, KM 55 RC
15
English
232BA017 KN
1
2
232BA018 KN
4
3
Cleaning the Air Filter
If there is a noticeable loss of engine
power
N Set the choke lever to g.
N Press in the tab (1) and swing the
filter cover (2) down.
N Clean away loose dirt from around
the filter.
Engine Management
Exhaust emissions are controlled by the
design of the fundamental engine
parameters and components (e.g.
carburation, ignition, timing and valve or
port timing) without the addition of any
major hardware.
N Remove the felt element (3) from
the filter housing (4) and replace it –
knock out or blow out as a
temporary measure – do not wash.
N Replace damaged parts.
N Fit the felt element (3) in the filter
housing (4).
N Close the filter cover so that it snaps
into position.
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KM 55 R, KM 55 RC
English
L
H
LA
233BA050 KN
Adjusting the Carburetor
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
With this carburetor it is only possible to
adjust the high speed screw within fine
limits.
Standard Setting
N Stopping the Engine
N Mount the KombiTool complete with
working tool or cutting attachment.
N Check the air filter and replace it if
necessary.
N Have the spark arresting screen in
the muffler checked (not all
markets) – see “Inspection and
Maintenance by Dealer"
N Turn high speed screw (H)
counterclockwise as far as stop (no
more than 3/4 turn).
N Turn the low speed screw (L)
carefully clockwise as far as stop,
then turn it back 1.5 turns.
N Start and warm up the engine.
N Adjust idle speed with the idle speed
screw (LA) so that the cutting
attachment does not move.
Fine Tuning for Operation in
Mountains or at Sea Level
A slight correction of the setting of the
high speed screw (H) may be necessary
if engine power is not satisfactory when
operating at high altitude or at sea level.
N Carry out the standard setting.
N Warm up the engine for about
3 minutes at full throttle.
Rule of thumb:
Turn the high speed screw (H) about
one quarter of a turn for every 1000 m
(3300 ft) change in altitude.
At high altitude
N Turn high speed screw (H)
clockwise (leaner) – no further than
stop.
At sea level
N Turn high speed screw (H)
counterclockwise (richer) – no
further than stop.
It is possible that maximum engine
speed may be reached with the standard
setting in each case.
Aadjusting Idle Speed
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed
screw (L).
N Warm up the engine for about 3
minutes.
Engine stops while idling
N Turn the idle speed screw (LA)
slowly clockwise until the engine
runs smoothly – the working tool or
cutting attachment must not move.
Cutting attachment runs when engine
is idling
N Turn the idle speed screw (LA)
counterclockwise until the working
tool or cutting attachment stops
KM 55 R, KM 55 RC
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English
1
232BA081 KN
000BA002 KN
moving and then rotate the screw
another 1/2 to 1 turn in the same
direction.
If the working tool or cutting
attachment continues to run when
the engine is idling, have your
machine checked and repaired by
your servicing dealer.
Erratic idling behavior, engine stops
even though setting of LA-screw has
been corrected, poor acceleration
Idle setting is too lean:
N Idle setting is too lean: Rotate the
low speed screw (L) about 1/4 turn
counterclockwise until the engine
runs and accelerates smoothly.
Erratic idling behavior
Idle setting is too rich
N Rotate the low speed screw (L)
about 1/4 turn clockwise until the
engine runs and accelerates
smoothly.
Spark Plug
If engine is down on power, difficult to
start or runs poorly at idling speed, first
check the spark plug.
Fit a new spark plug after approx. 100
operating hours or earlier if the
electrodes are badly eroded.
Wrong fuel mix (too much engine oil in
the gasoline), a dirty air filter and
unfavorable running conditions (mostly
at part throttle etc.) affect the condition
of the spark plug. These factors cause
deposits to form on the insulator nose
which may result in trouble in operation.
Removing the Spark Plug
N Move the stop switch to 0.
N Pull off the spark plug boot (1).
N Unscrew the spark plug.
Wrong fuel mix (too much engine oil in
the gasoline), a dirty air filter and
unfavorable running conditions (mostly
at part throttle etc.) affect the condition
of the spark plug. These factors cause
deposits to form on the insulator nose
which may result in trouble in operation.
If engine is down on power, difficult to
start or runs poorly at idling speed, first
check the spark plug.
N Remove spark plug – see "Starting /
Stopping the Engine".
N Clean dirty spark plug.
N Check electrode gap (A) and
readjust if necessary – see
"Specifications".
N Use only resistor type spark plugs of
the approved range.
Rectify problems which have caused
fouling of spark plug:
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KM 55 R, KM 55 RC
English
000BA036 TR
1
N Too much oil in fuel mix.
N Dirty air filter.
N Unfavorable running conditions,
e.g. operating at part load.
Fit a new spark plug after approx. 100
operating hours or earlier if the
electrodes are badly eroded.
Installing the spark plug
N Screw home the spark plug, fit the
boot and press it down firmly.
Engine Running Behavior
If engine running behavior is
unsatisfactory even though the air filter
is clean and the carburetor is properly
adjusted, the cause may be the muffler.
Have the muffler checked for
contamination (carbonization) by your
servicing dealer.
STIHL recommends that you have
servicing and repair work carried out
exclusively by an authorized STIHL
servicing dealer.
Warning!
To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. Always press spark plug boot (2)
snugly onto spark plug terminal (1) of
the proper size. (Note: If terminal has
detachable SAE adapter nut, it must be
attached.) A loose connection between
spark plug boot and ignition wire connector in the boot may create arcing that
could ignite combustible fumes and
cause a fire.
KM 55 R, KM 55 RC
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