Stihl Km 90 R Owners Manual

							{
STIHL KM 90 R
WARNING
Read Instruction Manual thoroughly 
before use and follow all safety 
precautions – improper use can 
cause serious or fatal injury.
ADVERTENCIA
Antes de usar la máquina 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 - 30
Manual de instrucciones
31 - 63 
						

							Original Instruction Manual Printed on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled. © ANDREAS STIHL AG & Co. KG, 2015
0458-465-8621-C. VA8.E15. 
0000000811_014_GB
KM 90 R
English
1
{This instruction manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process 
with electronic systems.
Contents
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. KombiSystem 2
Guide to Using this Manual 2
Safety Precautions and Working 
Techniques 3
Approved KombiTools 10
Mounting the Loop Handle 11
Adjusting the Throttle Cable 12
Fuel 12
Fueling 13
Starting / Stopping the Engine 14
Operating Instructions 16
Cleaning the Air Filter 16
Engine Management 16
Adjusting the Carburetor 17
Spark Arresting Screen in Muffler 17
Spark Plug 18
Storing the Machine 19
Inspections and Maintenance by 
Dealer 19
Maintenance and Care 20
Main Parts 22
Specifications 23
Maintenance and Repairs 24
Disposal 24
STIHL Incorporated Federal 
Emission Control Warranty 
Statement 25
STIHL Incorporated California 
Exhaust and Evaporative 
Emissions Control Warranty 
Statement 27
Trademarks 29 
						

							KM 90 R
English
2 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 KombiTool 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.
Pictograms
The meanings of the pictograms 
attached to or embossed on the 
machine are explained in this manual.
Depending on the model concerned, the 
following pictograms may be on your 
machine.
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:
NA 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:
NLoosen the screw (1).
NLever (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.
NOTICE
Indicates a risk of property damage, 
including damage to the machine or its 
individual components.
KombiSystem
.
.
.
.
002BA530 KN
+
+
*XLGHWR8VLQJWKLV0DQXDO
)XHOWDQNIRUJDVROLQH
DQGHQJLQHRLOPL[WXUH
3UHVVWRRSHUDWHGHFRP-
pression valve
Manual fuel pump
Press to operate manual 
fuel pump
Filler hole for gear 
lubricant
Air intake summer mode
Air intake winter mode
Handle heating 
						

							KM 90 R
English
3
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 differs from those 
described in this manual, please contact 
your STIHL dealer or the STIHL 
distributor for your area for assistance.
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
Safety Precautions and 
Working Techniques
Because this KombiEn-
gine is the engine for a 
high-speed power tool, 
special safety precau-
tions must be observed to 
reduce the risk of per-
sonal 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. 
						

							KM 90 R
English
4
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 
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
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.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.
Avoid loose-fitting jack-
ets, scarfs, neckties, 
jewelry, flared or cuffed 
pants, unconfined long 
hair or anything that 
could become caught on 
branches, brush or the 
moving parts of the unit. 
Secure hair so it is above 
shoulder level. 
						

							KM 90 R
English
5
THE POWER TOOL
For illustrations and definitions of the 
power tool parts see the chapter on 
"Main Parts."
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.Fuel
Your STIHL power tool uses an oil- 
gasoline mixture for fuel (see the 
chapter on "Fuel" of your instruction 
manual).
WARNING
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 
t o  r e l e a s e  s l o w l y .  N e v e r  r e m o v e  t h e  f u e l  
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
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. 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 combusti-
ble fuel vapor may 
escape from the fuel 
system.
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. 
						

							KM 90 R
English
6
WARNING
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
Check fuel system for leaks, especially 
the visible parts, e.g., filler cap, hose 
connections, manual fuel pump (only for 
power tools equipped with a manual fuel 
pump). Do not start the engine if there 
are leaks or damage – risk of fire! Have 
the machine repaired by a servicing 
dealer before using it.
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.
WARNING
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  Unit vibrations can cause 
an improperly tightened 
fuel filler cap to loosen or 
come off and spill quanti-
ties of fuel. In order to 
reduce the risk of fuel 
spillage and fire, tighten 
the fuel filler cap by hand 
as securely as possible. 
						

							KM 90 R
English
7 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.
WARNING
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
Never modify your muffler. Any 
modification could cause an increase in 
heat radiation, sparks or sound level, 
thereby increasing the risk of fire, burn 
injury or hearing loss. You may also 
permanently damage the engine. Have 
your muffler serviced and repaired by 
your STIHL servicing dealer only.
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. 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 
002BA057 KN
$VVRRQDVWKHHQJLQHLV
UXQQLQJWKLVSURGXFWJHQ-
erates toxic exhaust 
fumes containing chemi-
cals, such as unburned 
hydrocarbons (including 
benzene) and carbon 
monoxide, that are 
known to cause respira-
tory problems, cancer, 
birth defects, or other 
reproductive harm. Some 
of the gases (e.g. carbon 
monoxide) may be color-
less and odorless. To 
reduce the risk of serious 
or fatal injury/illness from 
inhaling toxic fumes, 
never run the machine 
indoors or in poorly venti-
lated locations. 
						

							KM 90 R
English
8 sitting on concrete, metal, bare ground 
or solid wood away from any 
combustible substances.
WARNING
An improperly mounted or damaged 
cylinder housing or a 
damaged/deformed muffler shell may 
interfere with the cooling process of the 
muffler. 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 muffler is furnished with a spark 
arresting screen designed to reduce the 
risk of fire from the emission of hot 
particles. Never operate your unit with a 
missing or damaged spark arresting 
screen. If your gas/oil mix ratio is correct 
(i.e., not too rich), this screen will 
normally stay clean as a result of the 
heat from the muffler 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. Some state or federal laws or 
regulations may require a properly 
maintained spark arrestor for certain 
uses. See the "Maintenance, Repair and 
Storing" section of these Safety 
Precautions. Remember that the risk of 
a brush or forest fire is greater in hot or 
dry conditions.
WARNING
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. 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 con-
ventional mufflers when 
the engine returns to idle 
or is shut off. To reduce 
the risk of fire and burn 
injuries when using a cat-
alytic converter, 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 materi-
als while it is still hot.