Shindaiwa HT2510 Owner's manual

DH2510
HT2510
SHINDAIWA OWNER’S/OPERATOR’S MANUAL
HT2510 HEDGE TRIMMER
DH2510 HEDGE TRIMMER
Part Number 62601-94310 Rev. 1/06
English ................... 1
Spanish................. 21
French................... 41
• Read this manual and familiarize yourself with its contents.
• This machine is designed for trimming hedges. Do not use this machine
for other purposes.
• Minimize the risk of injury to yourself and others.
• Do not operate or service this machine unless you clearly understand this manual.
• Keep this manual accessible so that you can reread it whenever you have a
question about its use.
WARNING!

2
Attention Statements
WARNING!
A statement preceded by the trian-
gular Attention Symbol and the word
"WARNING" contains information
that should be acted upon to prevent
serious bodily injury.
IMPORTANT!
The operational procedures described in
this manual are intended to help you get
the most from your unit, and to protect you
and others from harm. These procedures
are guidelines for safe operation under
most conditions, and are not intended to
replace any safety rules and/or laws that
may be in force in your area.
If you have questions regarding your
DH2510/HT2510 hedge trimmer, or if
you do not understand something in this
manual, your Shindaiwa dealer will be
glad to assist you. You may also contact
Shindaiwa, Inc., at the address printed on
the back of this manual.
IMPORTANT!
A statement preceded by the word
IMPORTANT is one that possesses
special significance.
CAUTION!
A statement preceded by the word
"CAUTION" contains information that
should be acted upon to avoid
damaging your unit.
Introduction
Introduction ................................................ 2
Attention Statements ................................. 2
General Safety Instructions ...................... 3
Safety and Equipment Labels ................... 4
Specifications .............................................. 5
Unit Description ......................................... 5
Assembly ..................................................... 6
Mixing Fuel ................................................ 9
Filling the Fuel Tank ................................. 9
Starting Procedure .................................. 10
Adjusting Engine Idle .............................. 11
Stopping the Engine ................................ 11
Maintenance and Adjustments ............... 12
Long Term Storage .................................. 15
Troubleshooting Guide ........................... 16
Declaration of Conformity ....................... 19
PAGE
The Shindaiwa DH2510/HT2510 hedge
Trimmer has been designed and built to
deliver superior performance and reliability
without compromise to quality, comfort,
or durability.
Shindaiwa high performance engines rep-
resent the leading edge of air-cooled engine
technology, delivering exceptionally high
power at remarkable low displacement and
weight. As an owner/operator, you’ll soon
discover for yourself why Shindaiwa is
simply in a class by itself!
IMPORTANT!
The information contained in this manual
describes units available at the time of
publication.
While every attempt has been made to
give you the very latest information about
your Shindaiwa product, there may be
some differences between your DH2510/
HT2510 hedge trimmer and what is
described here.
Shindaiwa Inc. reserves the right to make
changes to products without prior notifica-
tion, and without obligation to make altera-
tions to units previously manufactured.
Contents
NOTE:
A statement preceded by the word “NOTE”
contains information that is handy to know
and may make your job easier.
Read and follow this
manual and make sure
anyone using the hedge
trimmer does likewise.
Failure to do so could
result in serious injury or
machine failure. Keep
this manual for future
reference.
Always wear eye and
hearing protection
during the operation of
this hedge trimmer. A
hard hat will provide
additional security
against falling debris.
Sound Power Level
(measure in accordance
with 2000/14/EC).

3
ENGLISH
DH251003
Work Safely
Shindaiwa hedge trimmers operate at very high
speeds and can do serious damage or injury if
they are misused or abused. Never allow a person
without training or instruction to operate your
unit!
WARNING! Use Good Judgment
Stay Alert
You must be physically and mentally fit to
operate this unit safely.
General Safety Instructions
WARNING!
Never operate power
equipment of any kind if you are tired
or if you are under the influence of
alcohol, drugs, medication or any other
substance that could affect your ability
or judgement.
WARNING!
Minimize the Risk of Fire!
NEVER smoke or light fires near the
engine.
ALWAYS stop the engine and allow it
to cool before refueling. Avoid overfill-
ing and wipe off any fuel that may have
spilled.
ALWAYS move the unit to a place well
away from a fuel storage area or other
readily flammable materials before
starting the engine.
NEVER place flammable material close
to the engine muffler.
NEVER run the engine without the spark
arrester screen in place.
DO NOT OPERATE THIS UNIT
IF YOU ARE TIRED, ILL OR
UNDER THE INFLUENCE OF
ALCOHOL, DRUGS, OR
MEDICATION.
WARNING!
Never make unauthorized attachment
installations.
Avoid using or storing this
unit in a wet environment.
Water on the cutters may
enter the gearcase and
damage your unit.
Always wear eye, ear,
and hand protection while
operating this unit!
Always wear close-fitting clothing. Gloves offer
added protection and are strongly recommended.
Do not wear clothing or jewelry that could get
caught in machinery.
Always keep proper footing and do not
overreach. Maintain your balance at all
times during operation.
Use extreme caution when
operating near fences or
electric wiring.
Never cut metal objects or
wire with the blade.
Never operate this unit if
the safety guard has been
removed or damaged!
Never allow children to use
the unit. Avoid operating near
bystanders.
Always stop the engine
and install the blade cover
before moving to another
work site, and maintain a
firm footing while operating
or carrying the trimmer.
Always stop the
engine before
removing branches
or debris from the
cutters! Never allow
the cutters to contact
buildings or other
hard objects!
Avoid cutting large or extremely
“woody” branches. Doing so can
shorten cutter life, and may also
damage the gearcase.
WORK SAFELY!
Figure 1
ALWAYS wear eye protection to shield
against thrown objects.
ALWAYS protect yourself from haz-
ards such as thorny brush and flying
debris by wearing gloves and close
fitting clothing that covers arms and
legs. Never wear shorts. Don’t wear
loose clothing or items such as jewelry
that could get caught in machinery or
underbrush. Secure long hair so it is
above shoulder level.
NEVER run the engine when transport-
ing the unit.
NEVER run the engine indoors! Make
sure there is always good ventilation.
Fumes from engine exhaust can cause
serious injury or death.
ALWAYS clear your work area of trash
or hidden debris that could be thrown
back at you or toward a bystander.
ALWAYS use the proper cutting tool
for the job.
ALWAYS stop the unit immediately if it
suddenly begins to vibrate or shake.
Inspect for broken, missing or improp-
erly installed parts or attachments.
ALWAYS hold the unit firmly with
both hands when cutting or trimming,
and maintain control at all times.
ALWAYS keep the handles clean.
ALWAYS disconnect the spark
plug wire before performing any
maintenance work.
Always operate with
both hands firmly
gripping the unit.
WARNING!
Inspect front and rear handles for damaged or loose attachments before use.
NEVER operate a hedge trimmer with damaged or loose handles.

4
Safety Equipment and Labels
Cover
ON-OFF
Switch
Throttle Interlock
Protector
Caution Label
IMPORTANT!
Caution, Danger, Warning, and Opera-
tion Information Labels: Make sure all
information labels are undamaged and
readable. Immediately replace damaged
or missing information labels. New labels
are available from your local authorized
Shindaiwa dealer.
Figure 2
Cover
ON-OFF
Switch
Throttle Interlock
Protector
Caution Label
DH2510
HT2510
Warning Label

5
ENGLISH
WARNING!
Do not make unauthorized modifica-
tions or alterations to this machine or
any of its components or accessories.
Model Name ....................................................
Engine Model ..................................................
Engine Type ....................................................
Dry Weight (excluding cutting attachment) ........
Bore x Stroke ...................................................
Displacement ...................................................
Engine Speed at Maximum Power Output ...
Maximum Power Output ...............................
Engine Speed at Idling ...................................
Maximum Engine Speed ................................
Fuel/Oil Ratio ..................................................
Fuel Tank Capacity .........................................
Carburetor .......................................................
Ignition System ...............................................
Spark Plug ........................................................
Air Cleaner .......................................................
Starting Method ..............................................
Stopping Method .............................................
Dimensions (L x W x H) ................................
Sound Pressure Level* ..................... Idling
Racing
Sound Power Level*........................................
Vibration Level (Front/Rear)* ...... Idling
Racing
DH2510/EC2-2 DH2510/EC2-3
SHF2510EC2
4-cycle, horizontal-cylinder, air-cooled
5.9 kg 6.1 kg
34 mm x 27 mm
24.5 cm3
8,000 min-1 (RPM)
0.83 kW
3,000 min-1 (RPM)
10,500 min-1 (RPM)
50:1
550 cm3
Walbro WYJ, Diaphragm type
Fully Electronic, program controlled
NGK CMR5H
Non-reversible heavy-duty filter element
Recoil Starter
Slide Switch, grounding type
1100 x 245 x 230 mm 1220 x 245 x 230 mm
71dB (A) 72dB (A)
94dB (A) 97dB (A)
102dB (A) 103dB (A)
4.2/6.0 m/s2 3.2/5.0 m/s2
9.3/12.4 m/s2 10.0/12.7 m/s2
HT2510/EC2-3 HT2510/EC2-4
SHF2510EC2
4-cycle, horizontal-cylinder, air-cooled
5.7 kg 6.0 kg
34 mm x 27 mm
24.5 cm3
8,000 min-1 (RPM)
0.83 kW
3,000 min-1 (RPM)
10,500 min-1 (RPM)
50:1
550 cm3
Walbro WYJ, Diaphragm type
Fully Electronic, program controlled
NGK CMR5H
Non-reversible heavy-duty filter element
Recoil Starter
Slide Switch, grounding type
1100 x 240 x 230 mm 1410 x 240 x 230 mm
72dB (A) 71dB (A)
94dB (A) 93dB (A)
102dB (A) 103dB (A)
3.0/3.4 m/s2 4.8/4.9 m/s2
7.9/8.9 m/s2 13.6/10.7 m/s2
Air Cleaner
Cover
Fuel Tank
Gearcase
Choke
ON-OFF
Switch
Cover
Fuel Cap
Specifications
Unit Description
Prior to Assembly
Before assembling this product, please
make sure you have all the components
required for a complete unit:
• Engine assembly (powerhead)
• Cutter and gearcase assembly
• Rear handle
• Front handle
• Bolt package
•
Tool kit including, allen wrenches,
combination spark plug/13 mm
wrench
Carefully inspect all components for
damage.
IMPORTANT!
The terms “left,” “left-hand,” and
“LH”; “right,” “right-hand,” and “RH” ;
“front” and “rear” refer to directions as
viewed by the operator during normal
operation of this product.
Specifications are subject to change without notice.
Familiarize yourself with your
machine and its various components.
Understanding your machine helps
ensure top performance, long service
life, and safer operation.
DH2510
Air Cleaner
Cover
Fuel Tank
Protector
Gearcase
Throttle Trigger
Front Handle
Choke
Rear Handle
ON-OFF
Switch
Guide Bar
Cutter
Fuel Cap
Recoil
Starter
HT2510
Throttle
Trigger
Front Handle
Rear Handle
Guide Bar
Cutter
Recoil
Starter
Muffler
Protector
Protector
Cover
Muffler
Figure 3
* Sound Pressure Level: in accordance with ISO 22868 * Sound Power Level: in accordance with ISO 3744 and
ISO 11094 (average data between at idling and racing)
* Vibration Level: in accordance with EN 28662-1

6
Assembly HT2510
1. Temporarily remove the 5 mm x 12 mm
index bolt.
2. Loosen, but do not remove, the 5 mm x
25 mm clamp screw.
3. Position the rear handle assembly as
shown. Starting from the rear of the
trimmer, push the throttle cable, igni-
tion wire, and ground wire through the
handle mounting bracket.
4. Slide the rear handle into the handle
mounting bracket until it bottoms. Use
care to avoid pinching or otherwise
damaging the wires and cable.
  Align the hole in the rear handle
with the matching hole in the handle
mounting bracket, and then install
and firmly tighten the 5 mm x 12 mm
index bolt.
  Tighten the 5 mm x 25 mm clamp
screw firmly.
(1) Attaching the Rear Handle
to the Gearcase
 Orient the gearcase assembly to the
powerhead as shown, and secure
with the three 6 mm x 16 mm
screws.
1. Securely tighten screws A and B.
2. Push screw C through the eye ter-
minal in the throttle control ground
wire, and then install and firmly
tighten the screw to the powerhead.
(2) Installing the Powerhead
on the Gearcase (3) Install the Front Handle
Rear Handle
Assembly
Index Bolt
Throttle Cable,
Ignition, and
Ground Wires
Clamp Screw
WARNING!
Incorrect assembly could expose the operator to serious
injury! Read and follow assembly instructions carefully.
Powerhead
5 mm
Flange Nut
5 mm
Flange Nut
Front
Handle
Bolt
 The front handle is installed over a
5 mm bolt on the guide bar.
1. Install the 5 mm flange nut over the bolt
on the guide bar, and then tighten the
nut firmly.
Figure 4
Figure 6
Screw C
Screws A
and B
Figure 5

7
ENGLISH
(1) Attaching the Rear Handle
to the Gearcase Assembly
WARNING!
Incorrect as-
sembly could
expose the
operator to
serious injury!
Read and fol-
low assembly
instructions
carefully. Be-
fore attaching the rear handle,
make sure the rear handle
cushions are located correctly.
Assembly DH2510
1. Slide the rear handle onto the rear
flange of the cutter/gearcase assem-
bly. Make sure the throttle cable and
ignition and ground wires do not bind
during assembly.
2. Make sure the mating holes between
the rear handle and the gearcase are
aligned, then secure the rear handle us-
ing two 6 mm x 35 mm socket head cap
screws and washers.
IMPORTANT!
The washers used on the front handle and the
rear handle are not the same. The washers for
the rear handle are black for identification.
(2) Install the Front Handle
1. Locate the front handle onto the cutter/
gearcase assembly as shown.
2. Secure the handle using two 6 mm x
30 mm socket head cap screws and
washers.
(3)
Installing the Powerhead
on the Gearcase
 Orient the gearcase assembly and
powerhead as shown and secure with the
three 6 mm x 16 mm screws (A, B, and C).
1. Securely tighten screws A and B.
2. Push screw C through the eye termi-
nal in the throttle control ground wire
(black), and then install and firmly
tighten the screw to the powerhead.
6 mm x 30 mm socket
head cap screws and washers
Front Handle
Collar
Rear
Handle
Cushion
Cushion
Rear Handle
Assembly
Cutter/Gearcase
Assembly
6 mm x 35 mm
Socket Head Cap screws
and Washers (washers
black for identification)
Powerhead
Screw C
(6 x 16 mm)
Screws A and B
(6 x 16 mm)
Figure 7
Figure 9
Figure 10
Viewed from
the bottom
Throttle Cable,
Ignition and Ground
Wires
Figure 8

8
Assembly and Adjustments
Throttle Cable
Connect the Throttle Cable
1. Loosen the air cleaner cover knob
and remove the air cleaner cover.
See Figure 11.
2. Slip the throttle cable into the cable
adjuster and hook the bullet end of the
cable onto the swivel. See Figure 12.
Connect the Ignition Leads
3. Connect the ignition wires by pushing
the bullet connectors together. See
Figure 13.
4. Reinstall the air cleaner cover.
CAUTION!
Routing of wiring must not interfere
with throttle or choke operation.
If the unit does not return to idle speed or
doesen't reach full rpm, the throttle lever
free play may need to be adjusted as follows:
1. Measure free play at the end of the
throttle lever. Throttle lever free play
should be approximately 0.2-0.275"
(5-7 mm). See Figure 14.
2. If adjustment is necessary, remove the
air cleaner cover. Loosen the cable ad-
juster lock nut and turn the cable adjust-
ment fitting in or out until throttle lever
free play is approximately 0.2-0.275" (5-7
mm).
3. Replace the air cleaner cover, and tight-
en the cover retaining screw securely.
Assembly and Adjustments
Throttle Cable Free Play
0.2-0.275"
(5-7mm)
0.2-0.275"
(5-7mm) Throttle
Cable
Adjuster
Throttle
Cable
Adjuster
Lock Nut
Throttle
Cable
Figure 15
Throttle Lever
Free Play
Figure 14
Connect
the
Throttle
Cable
Ignition
Lead
Figure 12
Figure 11
Throttle
Cable
Cable
Adjuster
Air Cleaner
Cover
Figure 13
Cable
Swivel
Ignition
Lead
Knob

9
ENGLISH
WARNING!
Minimize the Risk of Fire!
 STOP the engine before refueling.
 ALWAYS allow the unit to cool
before refueling!
 ALWAYS store gasoline in a
container approved for flammable
liquids.
 Wipe all spilled fuel and move the
unit at least 10 feet (3 meters) from
the fueling point before restarting!
 NEVER start or operate this unit if
there is a fuel leak.
 NEVER start or operate this unit if
the carburetor, fuel lines, fuel tank
and/or fuel tank cap are damaged.
 NEVER smoke or light any fires near
the unit or fuels!
 NEVER place any flammable mate-
rial near the engine muffler!
 NEVER operate the engine without
the muffler and spark arrester in
place and properly functioning!
IMPORTANT!
Mix only enough fuel for your im-
mediate needs! If fuel must be
stored longer than 30 days and
oil with fuel stabilizer is not used,
it should first be treated with a
fuel stabilizer such as STA-BIL™.
Mixing Fuel
CAUTION!
This engine is designed to operate on
a 50:1 mixture consisting of unleaded
gasoline and ISO-L-EGD or JASO FC
class 2-cycle mixing oil only. Use of
non-approved mixing oils can lead to
excessive carbon deposits.
CAUTION!
 Some types of gasoline contain al-
cohol as an oxygenate. Oxygenated
gasoline may cause increased op-
erating temperatures. Under certain
conditions, alcohol-based gasoline
may also reduce the lubricating
qualities of some 2-cycle mixing oils.
 Never use any type of gasoline
containing more than 10% alcohol
by volume! Generic oils and some
outboard oils may not be intended
for use in high-performance 2-cycle
type engines, and should never be
used in your Shindaiwa engine.
 Use only fresh, clean unleaded gasoline
with a pump octane of 87 or higher.
 Mixed with 50:1 Shindaiwa ISO-L-EGD
or JASO FC class 2-cycle mixing oil at
a gasoline/ratio of 50:1. Shindaiwa One
meets or exceeds these requirements.
Oil is a registered JASO FC classi-
fied oil and also meets or exceeds ISO-L-EGD
performance requirements.Shindaiwa One is
recommended for use in all Shindaiwa low emis-
sions engines. Shindaiwa One also includes a
fuel stabilizer.
Filling the Fuel Tank
Gasoline 2-cycle mixing oil
liters milliliters
2.5 l ............................. 50 ml
5 l ............................100 ml
10 l ............................200 ml
20 l ............................400 ml
1. Place the unit on a flat, level surface.
2. Clear any dirt or other debris from
around the fuel filler cap.
3. Remove the fuel cap, and fill the tank
with clean, fresh fuel.
4. Reinstall the fuel filler cap and tighten
firmly.

10
Starting Procedure
2. Set the throttle trigger to the “fast idle”
position by performing the following:
a. Depress and hold the throttle lock,
and then squeeze the throttle trigger.
b. Depress and hold the “fast idle”
button.
c. While depressing the fast idle button,
release the throttle lock and throttle
trigger.
3. Prime the carburetor by repeatedly
depressing the carburetor primer bulb
until clear fuel can be seen flowing
through the transparent primer bulb.
Throttle
Trigger
Throttle
Lock
Fast Idle
Button
WARNING!
KEEP CLEAR OF THE CUTTING
ATTACHMENT DURING START-
ING OPERATIONS! THE CUTTERS
MAY MOVE WHEN THE ENGINE IS
STARTED!
 Place the trimmer on the ground
during all starting operations.
 Make sure you have a secure foot-
ing, and keep a firm grip on the unit
as well.
 Keep all bystanders and pets well
clear of the trimmer during starting
operations.
Choke
Closed
Figure 19
Figure 17
IMPORTANT!
Engine ignition is controlled by a two-position on-off switch mounted on the throttle
body. This switch is typically labeled “I” for ON and “O” for OFF.
If the engine does not start–
 Repeat the appropriate starting proce-
dure for a cold or warm engine.
 If the engine still fails to start, use
the procedures for “Starting a flooded
engine,” on the next page.
WARNING!
The cutting attachment will move
when the engine accelerates!
When the engine starts or fires–
1. Open the choke by moving the choke
lever backward (toward the fuel tank).
2. If the engine does not continue to run,
repeat the appropriate cranking proce-
dures for a cold or warm engine.
3. When the engine starts, clear excess
fuel from the combustion chamber by
accelerating the engine several times
with the throttle lever.
4. Operating the throttle will automatically
disengage the fast idle setting.
1. Place the unit on the ground. Grip the
engine cover with your left hand and
the starter handle with your right hand
(shown).
2. Pull the starter handle slowly toward
you until you feel the starter mechanism
engage.
3. Start the trimmer by pulling the starting
handle rapidly outward.
Cranking the Engine
Figure 20
1. Move the ignition stop switch to the rear
(towards the grip) to the “I” or ON posi-
tion. See Figure 16.
4. (Cold engine only) Choke the engine
by moving the choke lever forward to
the “closed” position. See Figure 19.
IMPORTANT!
The primer system only pushes fuel
through the carburetor. Repeatedly
pressing the primer bulb will not flood the
engine with fuel. Operation
 Squeezing the throttle increases engine
speed, causing the clutch to engage and
operate the cutters.
 Releasing the throttle decreases
engine speed, causing the cutters to
slow, and then stop altogether as the
clutch disengages.
 Use a sweeping motion when cutting,
and vary throttle settings often.
 Avoid cutting material larger than
1.27 cm in diameter.
CAUTION!
The recoil starter can be easily
damaged by abuse!
 Always engage the starter before
attempting to crank the engine.
 Never pull the starter cord to its full
length.
 Always rewind the starter cord
slowly.
DH2510
Figure 18
Throttle
Trigger
Throttle
Lock
Fast Idle
Button
HT2510
DH2510
Figure 16
HT2510
Ignition ON
Ignition
Switch
Ignition
Switch
Ignition ON
Primer Bulb
(viewed from rear)

11
ENGLISH
The engine must return to idle speed
whenever the throttle lever is released.
Idle speed is adjustable, and must be set
low enough to permit the engine clutch to
disengage the cutters.
Adjusting Engine Idle
Stopping the Engine
Idle
Adjustment
Screw
1. Cool the engine by allowing it to idle for
2–3 minutes.
2. Move the ignition switch to the “O” or
STOP position. See Figure 23.
WARNING!
The cutters must NEVER engage at
engine idle speeds! If the idle speed
cannot be adjusted by the above
procedure, return the trimmer to your
dealer for inspection.
Idle Speed Adjustment
1. Start the engine, and then allow it to idle
2–3 minutes until warm.
2. If the cutters move when the engine is
at idle, reduce idle speed by turning the
idle adjustment screw counterclockwise.
3. If a tachometer is available, the engine
idle speed should be final-adjusted to
3,000 ±250 rpm (min-1).
4. Carburetor fuel mixture adjustments
are preset at the factory and cannot be
adjusted or serviced in the field.
Figure 22
Starting a Flooded Engine
Spark
Plug
Spark Plug
Lead
CAUTION!
Incorrect spark plug installation can
damage the engine!
1. Disconnect the spark plug lead, and
then use the spark plug wrench to
loosen and remove the spark plug.
2. If the spark plug is fouled or is soaked
with fuel, clean or replace the plug as
necessary. For spark plug specifications
and gapping procedure, see page 13.
3. With the spark plug removed, crank the
engine several times to clear excess fuel
from the combustion chamber.
WARNING!
Burn danger from hot engine! Allow
engine to cool before removing
cylinder cover.
Figure 21
4. Replace the spark plug and tighten it
firmly with the spark plug wrench. If a
torque wrench is available, torque the
spark plug to 170-190 kg cm.
5. Repeat the starting procedures for a
warm engine.
6. If the engine still fails to start or fire,
refer to the troubleshooting chart at the
end of this manual.
DH2510
Figure 23
HT2510
Ignition OFF
Ignition
Switch
Ignition
Switch
Ignition OFF

12
Maintenance and Adjustments
IMPORTANT!
Maintenance, replacement or repair of
emission control devices and systems
may be performed by any repair estab-
lishment or individual; however, warranty
repairs must be performed by a dealer or
service center authorized by Shindaiwa
Kogyo Co., Ltd. The use of parts that are
not equivalent in performance and durabil-
ity to authorized parts may impair the ef-
fectiveness of the emission control system
and may have a bearing on the outcome
of a warranty claim.
WARNING!
Accidental start-ups can cause severe
injury! Before performing any main-
tenance on this equipment, stop the
engine and disconnect the spark plug!
1. Remove all grass clippings and dirt from
the hedge trimmer.

Remove any compacted debris from
around the fuel tank and/or muffler.

Inspect the engine cooling fins for
clogging, and clean as necessary.

Clean under the cylinder cover and
around the spark plug.

Inspect the air filter element for clog-
ging, clean as necessary.
Clean debris from
tank and muffler
Inspect cooling
fins, and clean as
required
Clean around
spark plug
Inspect/clean
air filter
element
Check cutters and
guide bar for damage
and that bolts
are tight
Lubricate
cutters
WARNING!
To reduce fire hazard, keep the engine
and muffler free of debris, leaves, or
excessive grease.
Keep cooling
fins clean
Keep cooling air
intake passages
clean
(Fuel tank removed
for clarity)
Daily Maintenance/Inspection
Figure 24
2. Check for loose, damaged, or missing
components, and repair as necessary.
3. Lubricate the cutters with oil before use,
and after refueling.
4. Check the cutters for damage and make
sure all bolts are tight.
Inspect front and rear handles for
damaged or loose attachments
10-Hour Maintenance
Every 10 hours of operation, (more
frequently in dusty or dirty conditions):
 Remove the air cleaner element from
the air cleaner housing and clean it
thoroughly with soap and water. Rinse
and dry thoroughly. Replace filter ele-
ment if necessary. See Figure 26.
CAUTION!
Do not operate the machine if the air
cleaner or element is damaged, or if
the element is water-soaked.
Figure 25
Figure 26
Air
Cleaner
Element
Air Cleaner
Cover

13
ENGLISH
 Remove and clean the cylinder cover and
clean grass and dirt from the cylinder fins.
Every 50 hours of operation
(more often in dusty or extreme
conditions)
Clean
Debris
Hooked
Wire
Figure 28
50 Hour Maintenance
Filter Element
Figure 29
Gearcase Lubrication
VIEWED FROM THE BOTTOM
Gearcase Grease Fitting
CAUTION!
 Over-lubricating may cause the
gearcase to run slower than normal,
and may also cause leakage from
excess grease.
Every 20 Hours
Figure 31
VIEWED FROM
THE BOTTOM
Gearcase
Cover
Figure 30
Top off gearcase grease level by using a le-
ver-type grease gun to force 1–2 strokes of
high quality lithium-based grease through
the gearcase grease fitting.
Every 100 Hours
(or before long-term storage)
Remove the gearcase cover, and use
solvent and a soft brush to remove all
old grease from the gearcase. To refill,
hand-pack the gearcase with approximately
40–50 grams of high quality lithium-based
grease (50–70% of capacity). DO NOT
OVERFILL!
341029
Every 10 to 15 hours of operation:
 Remove and clean the spark plug. Adjust
the spark plug electrode gap to 0.6 - 0.7
mm. If the spark plug must be replaced,
use only an NGK CMR5H or equivalent
resistor type spark plug of the correct
heat range. See Figure 27.
CAUTION!
Before removing the spark plug, clean
the area around the plug to prevent
dirt and debris from getting into the
engine’s internal parts.
Clean the spark plug
and check the gap at
the electrode.
10/15-Hour Maintenance
0.6–0.7 mm
Figure 27
NOTE:
The NGK CMR5H also meets the require-
ments for electro magnetic compliance (EMC).
CAUTION!
Make sure you do not pierce the fuel
line with the end of the hooked wire.
The line is delicate and can be dam-
aged easily.
 Use a wire hook to extract the fuel filter
from inside the fuel tank. (Figure XX).
Inspect the fuel filter element. If it shows
signs of contamination from debris,
replace it with a genuine Shindaiwa
replacement fuel filter element. Before
reinstalling the filter, inspect the fuel
line. If you discover damage or deterio-
ration, the unit should be removed from
service unitl it can be inspected by a
Shindaiwa-trained service technician.

14
139-Hour or Annual Maintenance
NOTE:
The NGK CMR5H also meets the require-
ments for electro magnetic compliance
(EMC).
Valve Adjustment
1. Remove cylinder cover, rocker arm cover,
and set piston at TDC-compression.
2. Loosen adjuster locknut so that the
2.5 mm Allen socket head adjustment
screw can turn freely.
3. Insert feeler gauge .004 (0.10 mm) for
both intake and exhaust; between valve
stem tip and rocker arm.
7. Replace rocker arm cover gasket to as-
sure proper sealing and install cover.
IMPORTANT!
If new gasket is not available and/or old
gasket is not damaged, old gasket may be
reused. Never use cracked or damaged
gaskets!
CAUTION!
 Performing a valve adjustment
incorrectly may cause hard starting
and/or can damage the unit. Refer to
the C4 Service Manual for complete
valve adjustment procedure and
torque specifications.
 If you are unfamiliar with this engine
or uncomfortable with this proce-
dure, Consult with an authorized
Shindaiwa servicing dealer.
4. Turn adjustment screw (clockwise =
tighter, counter-clockwise = looser) until
feeler gauge is almost snug. Back off
just enough to allow gauge to slip out
with limited resistance.
5. While holding adjustment screw in place
with Allen driver, tighten locknut with
wrench.
6. Turn engine over several times, and
return to TDC-compression. Recheck
with proper feeler gauge to make sure
clearance adjustment did not change as
a result of tightening locknut. Readjust
as necessary.
Figure 33
Figure 34
Figure 35
Maintenance after first 139-hours,
then every 150-hours thereafter.
 Combustion chamber should be decar-
bonized, and the valve clearance should
be adjusted. It is highly recommended
that this is done by a Shindaiwa-trained
service technician.
 Replace the spark plug annually: Use
only NGK CMR5H or equivalent resis-
tor type spark plug of the correct heat
range. Set spark plug electrode gap to
0.6 -0.7 mm.
HT2510_20
Blades
Standard blades require no periodic adjust-
ments. Make sure all blade shoulder bolts
are tight and in good condition.
 Clean blades and apply a light coating of
oil to all metal surfaces. Vegetable oils
may be used to protect sensitive plants
from spotting.
Locknut
Cutters
Socket Head
Shoulder Bolt
Plate
Guide Bar
Figure 32
Spacer

15
ENGLISH
Long Term Storage
Whenever the unit will not be used for 30
days or longer, use the following proce-
dures to prepare it for storage:
 Clean external parts thoroughly and
apply a light coating of oil to all metal
surfaces.
 Drain all the fuel from the carburetor
and the fuel tank.
IMPORTANT!
All stored fuels should be stabilized with a
fuel stabilizer such as STA-BIL™, if
oil with fuel stabilizer is not used.
Remove the remaining fuel from the fuel
lines and carburetor. With the fuel drained
from the fuel tank:
1. Prime the primer bulb until no more fuel
is passing through.
2. Start and run the engine until it stops
running.
3. Repeat steps 1 and 2 until the engine will
no longer start.
 Remove the spark plug and pour about
7.4 ml of 2-cycle mixing oil into the
cylinder through the spark plug hole.
Slowly pull the recoil starter 2 or 3 times
so oil will evenly coat the interior of the
engine. Reinstall the spark plug.
 Before storing the unit, repair or replace
any worn or damaged parts.
 Remove the air cleaner element from the
carburetor and clean it thoroughly with
soap and water. Let dry and reassemble
the element.
 Store the unit in a clean, dust-free area.
CAUTION!
Gasoline stored in the carbure-
tor for extended periods can cause
hard starting, and could also lead to
increased service and maintenance
costs.
Spark Arrester Screen Maintenance
If the engine becomes sluggish and low on
power, check and clean the spark arrester
screen.
WARNING!
Never operate the unit with a
damaged or missing muffler or spark
arrester! Operating with a missing
or damaged spark arrester is a fire
hazard and could also damage your
hearing.
1. With a 4 mm hex wrench remove the
3 engine cover screws and the engine
cover. See Figure 36.
2. With a 4 mm hex wrench remove the
3 muffler bolts and the muffler.
See Figure 36.
3. With a small flat bladed screwdriver
remove the 2 screws holding the spark
arrester screen and cover to the muffler.
See Figure 36.
4. Remove the screen and clean it with a
stiff bristle brush.
5. Inspect the cylinder exhaust port for any
carbon buildup.
IMPORTANT!
If you note excessive carbon buildup,
consult with an authorized Shindaiwa
servicing dealer.
6. Reassemble the spark arrester, muffler
and engine cover in the reverse order of
disassembly. Figure 36
Muffler
Bolts
Spark Arrester
Screen
Cover
Cover
Screws
Muffler
Gasket
Engine Cover
Screws
Muffler
Spark Arrester
Cover

16
Troubleshooting Guide
Vaporlock.
Valve adjustment.
Engine hot/heat soaked.
Low fuel quality.
Valve clearance too tight.
Valve clearance too loose.
Let cool completely and restart.
Refill with fresh, clean unleaded gasoline with a pump
octane of 87 or higher mixed with a 2-cycle air cooled
mixing oil that meets or exceeds ISO-L-EGD and/or
JASCO FC classified oils at 50:1 gasoline/oil ratio.
Adjust valves. See page 14.
What To Check Possible Cause Remedy
ENGINE DOES NOT START OR HARD TO START
NO
Does the engine crank?
Good compression?
Does the tank contain fresh fuel
of the proper grade?
Is fuel visible and moving in the
return line when priming?
Is there spark at the spark plug
wire terminal?
Check the spark plug.
Faulty recoil starter.
Fluid in the crankcase.
Internal damage.
Loose spark plug.
Excess wear on cylinder, piston, rings.
Fuel incorrect, stale, or contaminated;
mixture incorrect.
Check for clogged fuel filter and/or vent.
The ignition switch is in “O” (OFF) position.
Shorted ignition ground.
Faulty ignition unit.
If the plug is wet, excess fuel may
be in the cylinder.
The plug is fouled or improperly gapped.
The plug is damaged internally or
of the wrong size.
Consult with an authorized servicing dealer.
Tighten and re-test.
Consult with an authorized servicing dealer.
Refill with fresh, clean unleaded gasoline with a pump
octane of 87 or higher mixed with a 2-cycle air cooled
mixing oil that meets or exceeds ISO-L-EGD and/or
JASCO FC classified oils at 50:1 gasoline/oil ratio.
Clean as required. Restart.
Move switch to “I” (ON) position and re-start.
Consult with an authorized servicing dealer.
Crank the engine with the plug removed, reinstall the
plug, and restart.
Clean and regap the plug to 0.6 - 0.7mm. Restart.
Replace the spark plug with a NGK CMR5H or
equivalent spark plug of the correct heat range.
Adjust the spark plug electrode gap to 0.6 - 0.7 mm.
NO
YES
What To Check Possible Cause Remedy
ENGINE DOES NOT START
NO
YES
NO
YES
YES
NO
YES

17
ENGLISH
Is the engine overheating?
Engine is rough at all speeds.
May also have black smoke and/
or unburned fuel at the exhaust.
Operator is overworking the unit.
Carburetor mixture is too lean.
Improper fuel ratio.
Fan, fan cover, cylinder fins dirty or damaged.
Carbon deposits on the piston or in the muffler.
Clogged air cleaner element.
Loose or damaged spark plug.
Air leakage or clogged fuel line.
Water in the fuel.
Piston seizure.
Faulty carburetor and/or diaphragm.
Overheating condition.
Improper fuel.
Carbon deposits in the combustion chamber.
Cut at a slower rate.
Consult with an authorized servicing dealer.
Refill with fresh, clean unleaded gasoline with a pump
octane of 87 or higher mixed with a 2-cycle air cooled
mixing oil that meets or exceeds ISO-L-EGD and/or
JASCO FC classified oils at 50:1 gasoline/oil ratio.
Clean, repair or replace as necessary.
Consult with an authorized servicing dealer.
Service the air cleaner.
Tighten or replace. Replace the spark plug with a
NGK CMR5H or equivalent spark plug of the correct
heat range. Adjust the spark plug electrode gap to 0.6
- 0.7 mm.
Repair or replace fuel filter and/or fuel line.
Refill with fresh, clean unleaded gasoline with a pump
octane of 87 or higher mixed with a 2-cycle air cooled
mixing oil that meets or exceeds ISO-L-EGD and/or
JASCO FC classified oils at 50:1 gasoline/oil ratio.
Consult with an authorized servicing dealer.
See above.
Check fuel octane rating; check for presence of
alcohol in the fuel (page 9). Refuel as necessary.
Consult with an authorized servicing dealer.
What To Check Possible Cause Remedy
LOW POWER OUTPUT
Engine is knocking.
Troubleshooting Guide (continued)

18
Troubleshooting Guide (continued)
ADDITIONAL PROBLEMS
Poor acceleration.
Clogged air cleaner element.
Clogged fuel filter.
Carburetor mixture too lean.
Idle speed set too low.
Switch turned off.
Fuel tank empty.
Clogged fuel filter.
Water in the fuel.
Shorted spark plug or loose terminal.
Ignition failure.
Piston seizure.
Ground (stop) wire is disconnected,
or switch is defective.
Overheating due to incorrect spark plug.
Overheated engine
Engine idle too high.
Broken clutch spring or worn clutch spring boss.
Warped or damaged cutters.
Loose gearcase.
Damaged crankshaft/worn or damaged bushings.
Damaged/worn clutch.
Damaged gearcase
Clean the air cleaner element.
Replace the fuel filter.
Consult with an authorized servicing dealer.
Adjust: 3,000 (±250) RPM (min
-1
).
Reset the switch and re-start.
Refuel.
Replace fuel filter.
Drain and refill with fresh, clean unleaded gasoline
with a pump octane of 87 or higher mixed with a
2-cycle air cooled mixing oil that meets or exceeds
ISO-L-EGD and/or JASCO FC classified oils at 50:1
gasoline/oil ratio.
Clean and replace spark plug, tighten the terminal.
Consult with an authorized servicing dealer.
Test and replace as required.
Replace the spark plug with a NGK CMR5H or
equivalent spark plug of the correct heat range.
Adjust the spark plug electrode gap 0.6 - 0.7 mm.
Idle engine until cool. Refer to page 17.
(overheated engine).
Set idle: 3,000 (±250) RPM (min
-1
).
Replace spring/shoes as required, check idle speed.
Inspect and repair cutters as required.
Tighten gearcase securely
Inspect and replace as necessary.
Inspect and replace as required
Consult with an authorized servicing dealer.
Symptom Possible Cause Remedy
Engine stops abruptly.
Engine difficult to shut off.
Excessive vibration.
Cutting attachment moves at
engine idle.
Cutting attachment will not move.

19
ENGLISH
Declaration of Conformity

20
NOTES:
Shindaiwa Inc.
11975 S.W. Herman Rd.
Tualatin, Oregon 97062 USA
Telephone: [phone]
Fax: [phone]
www.shindaiwa.com
Shindaiwa Kogyo Co., Ltd.
Head Office:
6-2-11, Ozuka-Nishi
Asaminami-Ku, Hiroshima
731-3167, Japan
Telephone: [phone]
Fax: [phone]
©2005 Shindaiwa, Inc.
Part Number 62601-94310
Revision 1/06
Shindaiwa is a registered trademark
of Shindaiwa, Inc.
Specifications subject to change without notice.