STIHL HT 75, HT 70 Owner's Manual
STIHJ.:
Warning!
For safe operation follow all safety
precautions in Instruction Manual
use can cause serious injury.
Advertencia!
Para su seguridad durante el manejo de este
producto, siga siempre las precauciones de
seguridad dadas en el manual de
instrucciones-el uso indebido puede causar
lesiones graves.
improper
-
Contents
english
Guide to Using this Manual .............. 2
Safety Precautions ........................... 3
Using the Pole Pruner .................... 13
Mounting the Bar and Chain ........... 16
Tensioning the Saw Chain .............. 17
Checking Chain Tension ................. 17
Adjusting the Throttle
Cable* ............................................. 17
Fuel ................................................ 18
Printing inks contain vegetable oils;
paper can be recycled.
Fueling ............................................ 19
Chain Oil ......................................... 20
Filling Chain Oil Tank ...................... 20
Checking Chain Lubrication ........... 21
Adjusting Telescopic Shaft .............. 21
Fitting the Harness ......................... 22
Starting / Stopping
the Engine ...................................... 23
Operating Instructions .................... 27
Taking Care of Guide Bar ............... 28
Cleaning the Air Filter ..................... 28
Motor Management ........................ 29
Adjusting the Carburetor ................ 29
Spark Arresting Screen* in Muffler . 31
Checking the Spark Plug ................ 31
Printed on chlorine-free paper.© ANDREAS STIHL AG & Co. KG, 2003
Replacing the Starter Rope
and Rewind Spring ......................... 32
Storing the Machine ....................... 35
Checking the Chain Sprocket ......... 35
Replacing Chain Sprocket .............. 36
Maintaining and Sharpening
Saw Chain ...................................... 36
Maintenance Chart ......................... 41
Parts and Controls ......................... 42
Specifications ................................. 44
Special Accessories ....................... 45
Maintenance and Repairs .............. 45
STIHL Incorporated Federal
and California Emission Control
Warranty Statement ........................ 46
Allow only persons who understand this
manual to operate your pole pruner.
To receive maximum performance and
satisfaction from your STIHL pole
pruner, it is important that you read and
understand the maintenance and safety
precautions, starting on page 3, before
using your pole pruner.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
manual.
!Warning!
Because a pole pruner is a high-speed
cutting tool with a very long reach 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.
STIHL's philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements are made from time to time. If the
operating characteristics or the
appearance of your pole pruner differ
from those described in this manual,
please contact your STIHL dealer for
information and assistance.
* ........see “Guide to Using this Manual“
STIHl
0458 390 3021. M7. D3. PM. Printed in USA
1HT 70, HT 75
english
Guide to Using this Manual
Pictograms
All the pictograms attached to the
machine are shown and explained in
this manual.
The operating and handling instructions
are supported by illustrations.
Symbols in text
The individual steps or procedures
described in the manual may be marked
in different ways:
: Step or procedure without direct
reference to an illustration.
Description of step or procedure that
refers directly to the illustration and
contains item numbers that appear in
the illustration.
Example:
Loosen the screw (1)
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 described below:
Warning where there is a risk of an
accident or personal injury or
serious damage to property.
Warning where there is a risk of
damaging the machine or individual
components.
Note or hint which is not essential
for using the machine, but may
improve the operator’s understanding of the situation and result
in better use of the machine.
Note or hint on correct procedure in
order to avoid damage to the
environment.
Equipment and features
This instruction manual refers to
several models with different
features. Components that are not
installed in all models and related
applications are marked thus
Such components are available as
special accessories from your
STIHL dealer.
*.
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. If the
operating characteristics or the
appearance of your machine differ from
those described in this manual, please
contact your STIHL dealer for
assistance.
Therefore, we cannot be responsible for
changes, modifications or
improvements not covered in this
manual.
2
HT 70, HT 75
Safety Precautions
english
The use of any pole
pruner may be
hazardous. The pole
pruner chain has many
sharp cutters. If the
cutters contact your flesh,
they will cut you, even if the chain is not
moving. At full throttle, the chain speed
can reach 68 mph (30 m/s). It is
important that you read, fully understand
and observe the following safety
precautions and warnings. Read the
owner's manual and the safety
instructions periodically.
All safety precautions that are generally
observed when working with an axe or a
hand saw also apply to the operation of
pole pruners. However, because a pole
pruner is a high-speed, fast-cutting
power tool with a very long reach,
special safety precautions must be
observed to reduce the risk of personal
injury.
Have your STlHL dealer show you how
to operate your pole pruner. Observe all
applicable local safety regulations,
standards and ordinances.
!Warning!
Minors should never be allowed to use a
pole pruner. Bystanders, especially
children, and animals should not be
allowed in the area where a pole pruner
is in use. Never let the pole pruner run
unattended.
The pole pruner user is responsible for
accidents or risks involving third parties
or their property!
Do not lend or rent your
pole pruner without the
owner's manual. Be sure
that anyone using your
pole pruner reads and
understands the
information contained in
this manual.
These safety precautions and warnings
apply to the use of all STIHL pole
pruners. Different models may have
different parts and controls. See the
appropriate section of your owner's
manual for a description of the controls
and function of the parts of your model
pole pruner.
Safe use of a pole pruner involves:
1. the operator
2. the pole pruner
3. the use of the pole pruner
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 a pole pruner when you
are fatigued. Be alert – if you get tired
while operating your pole pruner, take a
break. Tiredness may result in loss of
control. Working with any pole pruner
can be strenuous. If you lack sufficient
strength to maintain control of the
pruner, do not use it. If you have any
condition that might be aggravated by
strenuous work, check with your doctor
before operating a pole pruner.
3HT 70, HT 75
english
!Warning!
Prolonged use of pole pruners (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 engine to the
operator's hands. An AV system is
recommended for those persons
using power tools on a regular or
sustained basis.
: Wear gloves and keep your hands
warm.
: Keep the AV system well
maintained. A pole pruner with
loose components or with damaged
or worn AV buffers will tend to have
higher vibration levels.
: Maintain a firm grip at all times, but
do not squeeze the handles with
constant, excessive pressures, 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 monitor closely the
condition of their hands and fingers. If
any of the above symptoms appear,
seek medical advice immediately.
!Warning!
The ignition system of your 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 pacemaker should
consult their physician and the
pacemaker manufacturer before
operating this tool.
Proper Clothing
Clothing must be sturdy
and snug-fitting, but allow
complete freedom of
movement. Avoid loosefitting jackets, scarves,
neckties, jewelry, flared or
cuffed pants, or anything that could
become entangled with the pruner or
brush. Wear overalls or jeans with
reinforced cut retardant inserts.
Wear gloves to improve
your grip and help protect
your hands when
handling the pole pruner
and saw chain. Heavy-
duty, nonslip gloves are
recommended.
Good footing is most
important in pole pruner
work. Wear sturdy boots
with nonslip soles. Steel-
toed safety boots are
recommended.
4
HT 70, HT 75
english
To reduce the risk of injury
to your eyes never
operate a pole pruner
unless wearing goggles or
properly fitted safety
glasses with adequate top
and side protection complying with
ANSI Z 87.1.
To reduce the risk of injury to your face,
STIHL recommends that you also wear
a face shield or face screen over your
goggles or safety glasses.
Wear an approved safety hard hat to
reduce the risk of head injury. Pole
pruner noise may damage your hearing.
Always wear sound barriers (ear plugs
or ear mufflers) to reduce the risk of
hearing loss. Continual and regular
users should have their hearing checked
regularly.
THE POLE PRUNER
For illustrations and definitions of the
parts of the pole pruner see the chapter
on "Parts and Controls" and
"Definitions".
!Warning!
Never modify a pole pruner in any way.
Only attachments and parts supplied by
STIHL or expressly approved by STIHL
for use with the specific STIHL pole
pruner models are authorized. Although
certain unauthorized attachments are
useable with the STIHL powerhead,
their use may, in fact, be extremely
dangerous.
Use the unit only with the recommended
saw chain and guide bar – a longer bar
makes the unit difficult to control.
THE USE OF THE UNIT
Transporting the pole pruner
!Warning!
Always stop the engine before putting a
pole pruner down or carrying it. Carrying
a pole pruner with the engine running is
extremely dangerous. Accidental
acceleration of the engine can cause the
chain to rotate.
!Warning!
During operation, the powerhead muffler
and the material around it reach
extremely high temperatures. Avoid
touching the hot muffler – you could
receive serious burns!
390BA000 KN
By hand: When carrying your pole
pruner by hand, the engine must be
stopped and the pole pruner must be in
the proper position. The chain guard
(scabbard) should be over the chain and
the guide bar, which should point
backwards. When carrying your pole
pruner, the bar should be behind you.
By vehicle: When transporting in a
vehicle, keep chain and bar covered with
the chain guard. Properly secure your
pole pruner to prevent turnover, fuel
spillage and damage to the pole pruner.
5HT 70, HT 75
english
Preparation for the use of the pole
pruner
Take off the chain guard and inspect for
safety in operation. For assembly, follow
the procedure described in the chapter
"Mounting the Bar and Chain" of your
owner's manual.
STIHL Oilomatic chain, guide bar and
sprocket must match each other in
gauge and pitch.
!Warning!
Proper chain tension is extremely
important. In order to avoid improper
setting, the tensioning procedure must
be followed as described in your
manual. Always make sure the hex
nut(s) for the sprocket cover is (are)
tightened securely after tensioning the
chain.
Never start the pole pruner with the
sprocket cover loose. Check chain
tension once more after having
tightened the nut(s) and thereafter at
regular intervals (whenever the pole
pruner is shut off). If the chain becomes
loose while cutting, shut off the engine
and then tighten. Never try to tighten the
chain while the engine is running!
Fueling
Your STIHL pole pruner uses an oilgasoline mixture for fuel (see chapter
"Fuel" of your owner's manual).
!Warning!
Gasoline is an extremely flammable fuel.
If spilled or ignited by a spark or other
ignition source, it can cause fire and
serious burn injury or property damage.
Use extreme caution when handling
gasoline or fuel mix.
To reduce the risk of fire or
burn injury, do not smoke
while using or standing
near the machine.
Combustible fuel vapor
may escape from the fuel
system.
Dust (e.g. wood dust), vapor (e.g. oil
mist from the chain lubricating system)
and smoke containing chemical
substances may be produced when
using this machine. These substances
may cause serious injuries and health
risks such as respiratory illnesses,
cancer, genetic defects or hereditary
damage.
If the risks associated with the possible
dust, vapor and smoke emissions are
not known, you should obtain the
relevant information from the contractor
or the responsible control body.
If it is not possible to avoid considerable
amounts of dust, vapor or smoke being
generated in spite of using the proper
working techniques, it is recommended
that the operator and bystanders wear
respirators approved for the substances
concerned.
Fueling Instructions
Fuel your pole pruner in well-ventilated
areas, outdoors only.
Always shut off the engine and allow it to
cool before refueling. Gasoline vapor
pressure may build up inside the gastank of a two cycle engine depending on
the fuel used, the weather conditions,
and the venting system of the tank.
6
HT 70, HT 75
english
In order to reduce the risk of burns or
other personal injury from escaping gas
vapor and fumes, remove the fuel cap
on the STIHL product carefully so as to
allow any pressure build-up in the tank
to release slowly. Never remove fuel
filler cap while engine is running.
Select bare ground for fueling and move
at least 10 feet (3 m) from fueling spot
before starting the engine. Wipe off any
spilled fuel before starting your pole
pruner, and check for leakage.
Check for fuel leakage while refueling
and during operation. If fuel or oil
leakage is found, do not start or run the
engine until leak is fixed and spilled fuel
has been wiped away. Take care not to
get fuel on your clothing. If this happens,
change your clothing immediately.
!Warning!
Unit vibrations can cause
an improperly tightened
fuel cap to loosen or come
off and spill quantities of
fuel.
In order to reduce risk of fuel spillage
and fire, tighten fuel cap by hand with as
much force as possible. Check fuel cap
periodically for tightness.
Starting
!Warning!
Your pole pruner is a one-person unit.
Do not allow other persons to be near
the running pole pruner. Keep
bystanders at least 15 m (50 ft) away.
Start and operate your pole pruner
without assistance.
For specific starting instructions, see the
appropriate section of the Owner's
Manual. Proper starting methods reduce
the risk of injury.
390BA022 KN
Place the pole pruner on firm ground or
other solid surface in an open area or in
the alternate as shown in the above
picture. Maintain a good balance and
secure footing.
!Warning!
To reduce the risk of injury from loss of
control, be sure that the guide bar and
chain are clear of you and all other
obstructions and objects, including the
ground. When the engine is started, the
engine speed with the starting throttle
lock engaged will be fast enough for the
clutch to engage the sprocket and turn
the chain. Never attempt to start the pole
pruner when the guide bar is in a cut or
kerf.
7HT 70, HT 75
english
When you pull the starter grip, do not
wrap the starting rope around your
hands. Do not allow the grip to snap
back, but guide the starter rope slowly
back to permit the rope to rewind
properly. Failure to follow this procedure
may result in injury to hand or fingers
and may damage the starter
mechanism.
Important adjustments
!Warning !
To reduce the risk of personal injury from
loss of control or contact with the
running chain, do not use a pole pruner
with incorrect idle adjustment. At correct
idle speed, the chain should not rotate.
For directions to adjust idle speed, see
the appropriate section of your owner's
manual. If you cannot set the correct idle
speed, have your STIHL dealer check
your pole pruner and make proper
adjustments or repairs.
After adjusting chain tension, start the
pole pruner, let the engine run for a
while, then switch engine off and
recheck chain tension. Proper chain
tension is very important at all times.
Working Conditions
Danger! Risk of Electrocution!
This pruner is not
insulated against electric
shock. Approaching or
contacting electric power
lines with a pruner may
cause death by
electrocution or serious bodily injury.
15m (50ft)
15m (50ft)
Electricity can jump from one point to
another by means of arcing. Higher
voltage increases the distance electricity
can arc. Electricity can also move
through branches, especially if they are
wet. Maintain a clearance of at least
15 m (50 ft) between the pruner
(including any branches it is contacting)
and any electrical line carrying live
current. Before working with less
clearance, contact your electric utility
and make sure current is turned off.
!Warning!
The pole pruner has a large range. In
order to reduce the risk of personal or
even fatal injury to bystanders from
falling objects and thrown pieces of
wood or in advertent contact with the
rotating chain of the pruner always keep
bystanders at least 15 m (50 ft) away
when the pole pruner is running.
Operate your pole pruner only outdoors
in a ventilated area.
!Warning!
Your pole pruner
produces toxic exhaust
fumes as soon as the
combustible engine is
running. These gases
(e.g. carbon monoxide)
may be colorless and
odorless.
To reduce the risk of serious or fatal
injury from breathing toxic fumes, never
run the pole pruner indoors or in poorly
ventilated locations.
8
HT 70, HT 75
english
!Warning!
Use of this product (including sharpening the saw chain) can generate dust,
mists and fumes containing chemicals
known to cause respiratory disease,
cancer, birth defects, or other
reproductive harm. If you are unfamiliar
with the risks associated with the
particular dust, mist or fume at issue,
consult your employer, governmental
agencies such as OSHA and NIOSH
and other sources on hazardous
materials. California and some other
authorities, for instance, have published
lists of substances known to cause
cancer, reproductive toxicity, etc. Control
dust (such as sawdust), mists (such as
oil mist from chain lubrication) and
fumes at the source where possible.
In this regard use good work practices
and follow the recommendations of
OSHA / NIOSH and occupational and
trade associations. When the inhalation
of toxic dust, mists and fumes cannot be
eliminated, the operator and any
bystanders should always wear a
respirator approved by NIOSH / MSHA
for the type substance at issue.
!Warning!
Breathing asbestos dust is dangerous
and can cause severe or fatal injury,
respiratory illness or cancer. The use
and disposal of asbestos containing
products have been strictly regulated by
OSHA and the Environmental Protection
Agency. Do not cut or disturb asbestos,
asbestos containing products (e.g.
asbestos containing drywall or other
construction products), or products such
as pipes which are wrapped or covered
with asbestos insulation. If you have any
reason to believe that you might be
cutting asbestos, immediately contact
your employer or a local OSHA
representative.
!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. Operate the pole pruner under good
visibility and daylight conditions only.
Don't work alone. Keep within calling
distance of others in case help is
needed.
!Warning!
Take extreme care in wet and freezing
weather and in slippery conditions (rain,
snow, ice). Put off the work when the
weather is windy, stormy or rainfall is
heavy.
!Warning!
Avoid stumbling on obstacles such as
stumps, roots or rocks and watch out for
holes or ditches. Be extremely cautious
when working on slopes or uneven
ground.
9HT 70, HT 75
english
!Warning!
To reduce risk of serious or fatal injury
from loss of control of the pole pruner
never attempt to operate any pole
pruner with one hand. Always hold the
pole pruner firmly with both hands.
Wrap your fingers tightly around the
control handle and shaft, keeping the
handle and shaft between your thumb
and forefinger.
Keep your hands in this position to have
your pole pruner under control at all
times. Make sure the handle and shaft
are in good condition and free of
moisture, pitch, oil or grease. Place your
left hand on front handle and your right
hand on rear handle and throttle trigger.
Left handers should follow these
instructions too.
!Warning!
Do not operate your pole pruner with the
starting throttle lock engaged. Cutting
with the starting throttle lock engaged
does not permit the operator proper
control of the pole pruner or chain
speed. Always cut at full throttle.
390BA026 KN
!Warning!
Never touch a chain with your hand or
any part of your body when the engine is
running, even when the chain is not
rotating. The chain continues to rotate
for a short period after the throttle trigger
is released.
Do not cut any material other than wood
or wooden objects. Use your pole pruner
for limbing only. It is not designed for
felling. It is not designed for prying or
shoveling away limbs, roots or other
objects.
When limbing, make sure that the saw
chain does not touch any foreign
materials such as rocks, fences, nails
and the like. Such objects may be flung
off and injure the operator or bystanders,
or damage the saw chain.
!Warning!
In order to keep control of your pole
pruner, always maintain a firm foothold.
Never work on a ladder, in a tree or on
any other insecure support. When
working at a height above 4.5 m (15 ft)
use a lift bucket.
For pole pruner with adjustable shaft:
Expand the shaft only as far as
necessary for the intended application.
!Warning!
Don't put pressure on the pole pruner
when reaching the end of a cut. The
pressure may cause the bar and rotating
chain to pop out of the cut or kerf, go out
of control and strike the operator or
some other object.
!Warning!
Prior to limbing, clear the working area
from interfering limbs and brush. Then,
establish a path of escape and remove
all obstacles.
10
HT 70, HT 75
english
max
60°
Keep work area clear – move away
fallen limbs. Place all tools and
equipment at a safe distance from the
branches being limbed, but not on the
escape path.
!Warning!
To reduce the risk of personal or even
fatal injury from falling objects do not cut
vertically above your body. Hold the pole
pruner at an angle of not more than 60°
from the horizontal level (see picture).
Objects may fall in unexpected
directions. Do not stand directly
underneath the limb being cut!
Watch for falling wood! As soon as the
limbed branch starts to fall, step aside
and keep distance away from the falling
wood.
!Warning!
Always observe the general condition of
the tree. Look for decay and rot in the
trunk and branches. If it is rotted inside,
it could snap and fall toward the operator
while being cut. Also look for broken or
dead branches which could vibrate
loose and fall on the operator.
If branch is thick or heavy, make a
shallow relief cut on the bottom of the
branch before cutting down from the top
to help prevent splitting of the branch.
Always pull the unit out of the cut with
390BA025 KN
the chain running to reduce the
possibility of pinching the cutting
attachment.
If the bar becomes pinched and caught
in the branch so that the chain can no
longer move, shut off the pruner and
carefully move the branch to open the
pinch and release the bar.
MAINTENANCE, REPAIR AND
STORING
!Warning!
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 claim
warranty for a component which has
not been serviced or maintained
properly or if nonapproved
replacement parts were used, STIHL
may deny warranty.
Never operate a pole pruner that is
damaged, improperly adjusted or not
completely or securely assembled.
Follow the maintenance and repair
instructions in the appropriate section of
your Owner's Manual, especially those
in the chapters " Mounting the Bar and
Chain" and "Maintaining and
Sharpening Saw Chain".
!Warning!
Use only STIHL replacement parts for
maintenance and repair. Use of parts
manufactured by others may cause
serious or fatal injury.
11HT 70, HT 75
english
!Warning!
Always shut off the engine and ensure
that the chain is stopped before
undertaking any adjustments,
maintenance or repair work, changing
the saw chain or cleaning the pole
pruner. Do not attempt any maintenance
or repair work not described in your
Owner's Manual. Have such work
performed at your STIHL service shop
only.
!Warning!
Never test the ignition system with
ignition wire terminal removed from
spark plug or with unseated spark plug,
since uncontained sparking may cause
a fire.
!Warning!
To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. Always press spark plug boot
snugly onto spark plug boot 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.
Keep spark plug clean, and make sure
ignition lead is in good condition.
!Warning!
Do not operate your pole pruner if the
muffler is damaged, missing or modified.
An improperly maintained muffler will
increase the risk of fire and hearing loss.
Never touch a hot muffler or burn will
result. If your muffler was equipped with
a spark-arresting screen to reduce the
risk of fire (e. g. in the USA, Canada and
Australia), never operate your pole
pruner if the screen is missing or
damaged. Remember that the risk of
forest fires is greater in hot or dry
weather.
Keep the chain, bar and sprocket clean;
replace worn sprockets or chains. Keep
the chain sharp. You can spot a dull
chain when easy-to-cut wood becomes
hard to cut or burn marks appear on the
wood.
Keep the chain at proper tension.
Tighten all nuts, bolts and screws except
the carburetor adjustment screws before
each use.
Additionally, the daily maintenance
schedule for your pole pruner set forth in
your STIHL Owner's Manual should be
strictly followed.
Store pole pruner in a dry place and
away from children. Before storing for
longer than a few days, always empty
the fuel tank.
For any maintenance please refer to the
maintenance chart and to the warranty
statement near the end of this manual.
Store fuel and chain oil in approved and
properly labeled safety-type canisters
only. Take care when handling gasoline!
Avoid direct contact with the skin and
avoid inhaling fuel vapor!
12
HT 70, HT 75
Using the Pole Pruner
english
Preparations
: Wear suitable protective clothing
and equipment – see chapter
"Safety Precautions".
: Adjust telescopic shaft to the
required length (HT 75 only).
: Start the engine.
: Put on the shoulder strap.
Never throw cuttings into the
household garbage can – cuttings
can be composted.
Never stand directly underneath the
branch you are cutting – be wary of
falling branches. Note that a branch
may spring back at you after it hits
the ground.
Cutting sequence
To allow branches a free fall, always cut
the lower branches first. Prune heavy
branches (large diameter) in several
controllable pieces.
Working techniques
Hold the control handle with your right
hand, and the shaft with your left hand.
Your left arm should be extended to the
most comfortable position.
HT 70:
Always hold the shaft with your left hand
in the area of the handle hose.
The most convenient working position is
a tool angle of 60°, but any lesser angle
may be used to suit the situation
concerned.
Cross-cut
390BA052 KN
Position the cutting attachment with the
hook against the branch and then
perform the cross-cut.
The shaft should always be held at an
angle of 60° or less.
390BA018 KN
13HT 70, HT 75
english
2
1
Relieving cut
: To avoid kickback, pinching the bar
or tearing the bark when pruning
thick branches, always start by
performing a relieving cut (1) on the
underside of the branch.
: To do this, apply the cutting
attachment and pull it across the
bottom of the branch as far as the
bar nose.
: Locate the hook against the branch
and then perform the cross-cut (2).
A
4
390BA041 KN
Flush-cutting thick branches
: If branch diameter is more than 4“
(10cm), first perform undercut (3)
and then cross-cut at a distance of
about 8“ (20cm) (A) from the final
cut.
Then carry out the flush-cut (4),
starting with a relieving cut and
finishing with a cross-cut.
3
390BA024 KN
Cutting above obstacles
The unit's long reach makes it possible
to prune branches that are overhanging
obstacles, such as rivers or lakes. The
tool angle in this case depends on the
position of the branch.
390BA020 KN
14
HT 70, HT 75
english
1
2
Cutting from a lift bucket
The unit's long reach enables cutting to
be performed next to the trunk without
the risk of the lift bucket damaging other
branches. The tool angle depends on
the position of the branch.
390BA017 KN
30° angle drive
(special accessory for HT 70)
The angle drive keeps the cutting
attachment at an angle of 30° to the
drive tube.
The angle drive may be adjusted on the
drive tube to the following positions only:
1: For cross-cutting vertical branches
and bushes.
2: For a better view of the cutting
attachment.
390BA053 KN
15HT 70, HT 75
english
Mounting the Bar and Chain
: Unscrew nut and take off cover.
1
2
: Turn tensioning screw (1)
counterclockwise until the
tensioning nut (2) butts against the
left end of the housing slot, then
back it off 5 full turns.
390BA042 KN
390BA043 KN
The chain is very sharp – wear work
gloves to protect hands from cuts.
: Fit the chain –
start at the bar nose.
5
: Fit guide bar over the stud (3).
Engage peg of tensioner slide in
locating hole (4) – place the chain
over sprocket (5) at the same time.
: Now turn tensioning screw (1)
clockwise until there is very little
chain sag on the underside of the
390BA003 KN
bar – and the drive link tangs are
located in the bar groove.
: Refit the sprocket cover and screw
on the nut only fingertight.
: Now refer to "Tensioning the Saw
Chain".
1
3
4
390BA044 KN
16
HT 70, HT 75
english
Tensioning the Saw Chain
1
Retensioning during cutting work:
: Shut off the engine and then
slacken the nut.
: Hold the bar nose up.
: Use screwdriver to turn the
tensioning screw (1) clockwise until
chain fits snugly against the
underside of the bar.
Tighten down the nut firmly.
A new chain has to be retensioned more
often than one that has been in use for
some time – check chain tension
frequently – see chapter "Operating
Instructions / During Operation“.
: Check chain tension.
Checking Chain Tension
390BA045 KN
: Shut down the engine.
: Wear work gloves to protect hands.
: Chain must fit snugly against the
underside of the bar and it must still
be possible to pull the chain along
the bar by hand.
: If necessary, retension the chain.
A new chain has to be retensioned more
often than one that has been in use for
some time.
Check chain tension frequently –
see chapter "Operating Instructions /
During Operation“.
Adjusting the Throttle Cable*
A properly adjusted throttle cable is
the precondition for correct
operation in the full throttle, starting
throttle and idle positions.
Adjust the throttle cable only after
the unit is fully assembled.
390BA046 KN
002BA163 KN
: Use a suitable tool to push the slide
to the bottom of the slot (see
illustration).
* see "Guide to Using this Manual"
17HT 70, HT 75
english
Fuel
1
2
: Press down the trigger interlock (1)
and squeeze the throttle trigger (2)
(full throttle) – this sets the throttle
cable correctly.
This engine is certified to operate on
unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1.
Your two-stroke engine requires a
mixture of brand-name gasoline and
quality two-stroke air cooled engine oil.
Use mid-grade unleaded gasoline with a
002BA161 KN
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
nationally recognized name brand
unleaded gasoline!
Use only STIHL two-stroke engine oil or
equivalent branded two-stroke engine
oils that are designed for use only in air
cooled two-cycle engines.
We recommend STIHL 50:1 two-stroke
engine oil since it is specially formulated
for use in STlHL 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.
18
HT 70, HT 75
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.
english
Fueling
Gasoline
Oil (STIHL 50:1 or
equivalent branded oils)
US gal. US fl.oz
12.6
2 1/2 6.4
512.8
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
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 build-up
in the tank to release slowly.
After fueling, tighten fuel cap
as securely as possible by hand.
389BA031 KN
Change the fuel pick up body every year.
Before storing your machine for a long
period, drain and clean the fuel tank and
run engine until carburetor is dry.
Checking oil level
Check chain oil level in tank at
regular short intervals and fill up as
necessary.
389BA032 KN
19HT 70, HT 75
english
Chain Oil Filling Chain Oil
Tank
For automatic and reliable
lubrication of the chain and guide
bar: Use only a quality,
environmentally compatible
chain and bar lubricant. STIHL
chain lubricant with non-fling
additive or the rapidly
biodegradable STIHL BioPlus is
recommended.
Biological chain oil must be resistant
to aging (e.g. STIHL BioPlus) since
it will otherwise quickly turn to resin.
This results in hard deposits that are
difficult to remove, especially in the
area of the chain drive and chain. It
may even cause the oil pump to
seize.
The service life of the chain and guide
bar depends on the quality of the
lubricant. It is therefore essential to use
only a specially formulated chain
lubricant!
If special chain lubricant is not available,
you may – in an emergency – use an HD
single grade or multigrade engine oil
with a viscosity that suits the prevailing
outside temperature.
Do not use waste oil! Waste oil
does not have the required
lubricating properties and is
unsuitable for chain lubrication.
Medical studies have shown that
renewed contact with waste oil can
cause skin cancer. It also harms the
environment!
390BA047 KN
A full chain oil tank is sufficient for
about one tankful of fuel. Check the
oil level regularly during cutting
work. Never allow the oil tank to run
dry!
: Thoroughly clean the filler cap and
area around it so that no dirt can fall
into the tank.
: Position the unit so that the filler cap
faces up.
If the oil level in the tank does not
change, this may be due to a problem in
the oil supply: Check chain lubrication,
clean the oilways, contact your STlHL
dealer for assistance if necessary.
20
HT 70, HT 75
english
1
2
The bayonet-type oil tank filler cap with
its hinged clip can be opened and closed
without tools.
: To open the tank, swing the clip (1)
to the vertical position.
: Turn the filler cap counterclockwise
as far as stop and remove.
: Fill up with chain oil.
: To close the oil tank, place the filler
cap in position with the clip vertical,
making sure the recesses (2) are in
alignment.
: Turn the filler cap clockwise as far
as stop.
: Fold the clip down so that it is flush
with the top of the cap.
Checking Chain Lubrication
247BA011 KN
The saw chain must always throw off a
small amount of oil.
: Always check chain lubrication and
the oil level in the tank before
starting work.
Never operate your pruner without
chain lubrication. If the chain is run
dry, the whole cutting attachment
will be irretrievably damaged within
a very short time.
Inadequate lubrication can be caused by
a dirty oil strainer: Have the oil strainer
cleaned or replaced by your STIHL
dealer.
Every new chain has to be broken in
for about 2 to 3 minutes.
After breaking in the chain, check
chain tension and adjust if
necessary – see chapter
"Checking Chain Tension".
Adjusting Telescopic Shaft
(HT 75)
390BA048 KN
Always shut down the engine and put
on the chain guard!
: Slacken off the screw.
: Adjust shaft to required length.
: Tighten the screw firmly.
390BA049 KN
390BA049 KN
21HT 70, HT 75
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Fitting the Harness
2
2
1
1
1
Shoulder strap*
: Put on the shoulder strap (1).
: Adjust length of strap so that the
spring hook (2), with the unit
attached, is at about the same
height as your right hip.
* see “Guide to Using this Manual“
3
390BA040 KN
390BA040 KN
Full harness*
: Put on the full harness (1) and
sling (2) as shown on the instruction
sheet supplied.
: Adjust the harness and thigh belt (3)
as required.
: Rest the powerhead in the sling
during cutting work.
*see “Guide to Using this Manual”
2
386BA012 KN
22
HT 70, HT 75
Starting / Stopping the Engine
english
3
2
4
6
5
STOP
3
Controls
Throttle trigger interlock (1), throttle
trigger (2) and slide control (3) with the
positions:
START (4)
The normal run position # (5)
and
$ – STOP (6) for stopping the engine..
1
Starting
: Hold down the trigger interlock and
squeeze the throttle trigger.
: Keep both levers in that position.
: Move the slide control to START
position and hold it there.
: Now release the throttle trigger,
slide control and trigger interlock in
that order. This is the
starting-throttle position.
8
9
002BA149 KN
If engine is cold:
Set the choke lever (8) to g
If engine is warm:
Set the choke lever (8) to e
Also use this setting if engine has been
running but is still cold.
: Press the fuel pump bulb (9) at least
five times, even if the bulb is still
filled with fuel.
8
393BA017 KN
393BA018 KN
23HT 70, HT 75
english
390BA022 KN
: Place the unit on the ground:
It must rest securely on the engine
support and the hook.
: Remove the chain guard.
Check that chain is not touching any
object or the ground.
If necessary, rest the hook on a
raised support (e.g. a branch,
mound or something similar).
Check that nobody is standing
within the working range of the
pruner.
.
24
: Make sure you have a firm footing:
Press the unit firmly against the
ground with your left hand on the fan
housing. Your thumb should be
under the fan housing.
Do not stand or kneel on the
drive tube. This will bend the tube
and result in permanent damage to
the telescopic shaft.
HT 70, HT 75
Alternative method:
: Remove the chain guard.
Position the shaft on a branch so
that it is held by the hook.
: Hold the unit firmly with your left
hand around the fan housing – your
thumb under the fan housing.
: Pull the starter grip slowly with your
right hand until you feel it engage –
and then give it a brisk strong pull.
Do not pull out starter rope to full
length – it might break.
: Do not let the starter grip snap back
– guide it slowly into the housing so
that the starter rope can rewind
properly.
When engine begins to fire:
: Move choke lever to e
: continue cranking.
As soon as engine runs:
: Blip the throttle trigger – the slide
control moves to the run position #,
and the engine returns to idling
speed.
Make sure carburetor is correctly
adjusted – chain must not run when
engine is idling.
Your pruner is ready for operation.
To shut down engine:
390BA009 KN
: Move the slide control in direction
of c to $.
english
25HT 70, HT 75
english
At very low temperatures
As soon as engine runs:
: Blip the throttle trigger – the slide
control moves to the run position #,
and the engine returns to idling
speed.
: Open throttle slightly – warm up
engine for short period.
If the engine does not start
If you did not move the choke to e
quickly enough after the engine began to
fire, the combustion chamber is flooded.
: Set choke lever to e.
: Set slide control, interlock lever and
throttle trigger to starting throttle
position.
: Start the engine – pull the starter
rope briskly – 10 to 20 pulls may be
necessary.
10
If the engine still does not start
: Move the slide control in direction of
c to STOP – $.
: Pull off the spark plug boot (10).
: Unscrew and dry off the spark plug.
: Open the throttle fully.
: Pull the starter rope several times
to clear the combustion chamber.
: Fit the spark plug – use combination
wrench to tighten it down.
: Connect the spark plug boot and
press it down firmly.
: Move the slide control to START.
: Set choke lever to e
even if engine is cold.
: Now start the engine.
Throttle cable
Check adjustment of the throttle cable –
see "Adjusting the Throttle Cable".
Fuel tank run until dry
: After refueling, press the fuel pump
393BA019 KN
bulb at least fives times – even if the
bulb is filled with fuel.
: Set choke lever to suit engine
temperatire.
: Now start the engine.
26
HT 70, HT 75
Operating Instructions
english
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.
Do not make the mixture leaner to
achieve an apparent increase in
power – this could damage the
engine – see chapter “Adjusting the
Carburetor”.
During operation
Check chain tension frequently!
A new chain has to be tensioned more
often than one that has been in use for
some time.
Cold chain
Tension is correct when the chain fits
snugly against the underside of the bar
and can still be pulled along the bar by
hand.
Retension if necessary –
see chapter “Tensioning the Saw Chain”.
Chain at operating temperature
The chain stretches and begins to sag.
The drive links on the underside of the
bar must not come out of the bar groove
– the chain may otherwise jump off the
bar.
Retension the chain –
see chapter “Tensioning the Saw Chain”.
Always slacken off the chain again
after finishing work. The chain
contracts as it cools down. If it is not
slackened off, it may damage the
crankshaft and bearings.
After a long period of full-throttle
operation
Allow engine to run for a while at idle
speed so that the heat in the engine can
be dissipated by flow of cooling air. This
protects engine-mounted components
(ignition, carburetor) from thermal
overload.
After finishing work
: Slacken off the chain if you have
retensioned it at operating
temperature during cutting work.
The chain contracts as it cools down. If it
is not slackened off, it may damage the
crankshaft and bearings.
Wait for engine to cool down. Drain the
fuel tank. Store the machine in a dry
place. Check tightness of nuts and
screws (not adjusting screws) at regular
intervals and retighten as necessary.
27HT 70, HT 75
english
Taking Care of Guide Bar
2
1
: Turn the bar over –
every time you sharpen the chain –
and every time you replace the
chain – this avoids one-sided wear,
especiallly at nose and underside of
the bar.
Regularly clean
1 = oil inlet hole
2 = oil passage
3 = bar groove
3
: Measure groove depth –
with scale on filing gauge – see
“Special Accessories“ – in area
used most for cutting on Rollomatic
bars.
Chain type Chain pitch Minimum
groove depth
Picco-Mini 3/8" P 5.0 mm
(0.20")
If groove depth is less than specified:
: Replace the guide bar.
The drive link tangs will otherwise
390BA050 KN
scrape along the bottom of the groove –
the cutters and tie straps will not ride on
the rails.
Cleaning the Air Filter
2
1
355BA014 KN
Dirty air filters reduce engine power
increase fuel consumption and make
starting more difficult.
If there is a noticeable loss of engine
power
: Move choke lever to g.
: Press in the tab (1).
: Ease the filter cover (2) over the tab
and take it away.
: Clean away loose dirt from around
the filter.
: Remove the foam and felt filter
elements.
28
HT 70, HT 75
english
Motor Management Adjusting the Carburetor
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.
HL
3 / 4
1
2
3
355BA031 KN
4
: Wash the foam element in a clean,
non-flammable cleaning solution
(e.g. warm soapy water) and then
dry.
: Fit new felt element.
As a temporary measure you can
knock it out on the palm of your
hand or blow it out with compressed
air. Do not wash.
Replace damaged parts!
: Install the foam element (3) in the
filter cover (2).
: Place felt element (4) (lettering
facing inward) in filter housing (5).
: Fit filter cover so that it snaps into
position.
5
355BA032 KN
LA
265BA024 KN
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 possibleto
adjust the engine idle speed within fine
limits.
29HT 70, HT 75
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