Hitachi CS 51EA User Manual

Chain Saw
Model CS 51EA

Handling instructions

Note:
Before using this machine, carefully read through these HANDLING INSTRUCTIONS
to ensure effi cient, safe operation. It is recommended that these INSTRUCTIONS be
kept readily available as an important reference when using this machine.

English

MEANINGS OF SYMBOLS

NOTE: Some units do not carry them.

Symbols

WARNING

The following show symbols used for the machine. Be sure that you understand their meaning before use.
It is important that you read, fully understand and

observe the following safety precautions and
warnings. Careless or improper use of the unit may
cause serious or fatal injury.

Read, understand and follow all warni ngs and
instructions in this manual and on the unit.

Emergency stop

Fuel and oil mixture

Always wear eye, head and ear protectors when using
this unit.

Warni ng, kickback danger. Be careful of possible
sudden and accidental upward and/or backward
motion of the guide bar.

One-handed usage not permitted. While cutting, hold
saw fi rmly with both hands with thumb fi rmly locked
around front handle.

Chain brake Carburetor adjustment - High speed mixture

Choke Oil pump adjustment

On/Start Priming pump

Off /Stop Decompression valve

Contents

WHAT IS WHAT? .............................................................................. 3

WARNINGS AND SAFETY INSTRUCTIONS .................................. 3

SPECIFICATIONS ............................................................................ 5

ASSEMBLY PROCEDURES ............................................................. 5

OPERATING PROCEDURES ........................................................... 6

MAINTENANCE .............................................................................. 10

Parts breakdown

Chain oil fi ll

Carburetor adjustment - Idle speed

Carburetor adjustment - Low speed mixture

2

English

15

17

WHAT IS WHAT?

1. Throttle lever: Device activated by the operatorʼs fi nger, for
controlling the engine speed.

2. Throttle lever lockout: Device that prevents the accident al
operation of the throttle lever until manually released.

3. Stop switch: Device for allowing the engine to be started or
stopped.

4. Oil tank cap: For closing

5. Recoil starter: Pull handle to start the engine.

6. Front handle: Suppor t handle located at or towar ds the front of
the engine housing.

7. Fuel tank cap: For closing the fuel tank.

8. Choke lever: Device for enriching the fuel/air mixture in the
carburetor, to aid

9. Priming pump; Device for supplying extra fuel, to aid starting.

10. Decompression va lve: Device for reducing the compression
pressure to aid starting.

11. Guide bar: The part that supports and guides the saw chain.

12. Saw chain: Chain, serving as a cutting tool.

13. Cha in brake (Fro nt hand guard):
the chain.

14. Spiked bumper: Device for acting as a pivot when in contact with
a tree or log.

15. Cha in catcher: Device for restraining the saw chain.

16. Guide bar cover: Device for covering the guide bar and saw
chain when the unit is not

17. Combi box spanner: The tool for removing or installing a spark
plug and tensioning the saw chain.

18. Handling instructions: Included with unit. Read before operation
and keep for future reference to learn proper, safe techniques.

the oil tank.

starting.

Device for stopping or locking

being used.

16

17

16

10

13

2

8

9

15

14

12

11

6

5

1

4

37

18

WARNINGS AND SAFETY INSTRUCTIONS

Operator safety

○ Always wear a safety face shield or goggles.
○ Gloves should be used when sharpening chain.
○ Always wear safety protective equipment such as jacket,

trousers, gloves, helmet, boots with steel toe-caps and non-slip
soles, and eye, ear and leg protection equipment whenever you
use a chain saw. For
suitable for climbing techniques. Do not wear loose clothing,
jewelry, short pants, sandals or go barefoot.

Secure hair so it is above shoulder length.
○ Do not operate this too l when you are tired, ill or under the

infl uence of alcohol, drugs

○ Never let a child or inexperienced per son operate the machine.
○ Wear hearing protection. Pay attention to your surroundings.

Be aware of any bystanders who may be signaling a problem.
Remove safet y equipment immediately upon shutting off engine.

○ Wear head protection.
○ Never start or run the engine

Breathing exhaust fumes can kill.

○ For respirator y protection, wea r a protection mask while emitting

the chain oil mist and dust from sawdust.

○ Keep handles free of oil and fuel.
○ Keep hands away from cutting equipment.
○ Do not grab or hold the unit by
○ When the unit turned o ff , make sure the cut ting attachment has

stopped before the unit is set down.

working in trees the safet y boots must be

or medication.

inside a closed room or building.

the cutting equipment.

○ When operation is prolonged, take a break from time to time

so that yo u may avoid possible Hand-Arm Vibration Syndrome
(HAVS) which is caused by vibration.
The operator must obey the local regulations of cutting area.

○

WARNING

○ Antivibration systems do not guarantee that yo u will not sustain

Hand-Arm Vibration Syndrome or carpal tunnel syndr ome.

Therefore, continual end regular users should monitor closely

the condition of their hands and fi ngers. If any of the above
symptoms appear, seek medical advice immediately.

○ Long or continuous ex posure to high

permanent hearing impairment. Always wear approved hearing
protection when operating a unit/machine.

○ If you are using any medical electric/electronic devices such

as a pacemaker, consult your physician as well as the device
manufacturer prior to operating any power equipment.

Unit/machine safety

○ Inspect the entire unit/machine before

damaged parts. Check for fuel leaks and make sure all fasteners
are in place and securely tightened.

○ Replace parts that are cracked, chipped or damaged in any way

before using the unit/machine.

○ Make sure the side case is properly attached.
○ Keep others away when making carburetor
○ Use only accessories as recommended for this unit/machine by

the manufacturer.

○ Never let the chain strike any obstacle. If the chain makes

contact, the machine should be stopped and checked carefully.

noise levels may cause

each use. Replace

adjustments.

3

English

○ Make sure the automatic oiler is working. Keep the oil tank fi lled

with clean oil. Never let chain run dry on the bar.

○ All chain saw service, other than the items listed in the

operatorʼs/ ownerʼs manual, should be performed by competent
chain-saw service personnel. (For example,
used to remove the fl y wheel or if an improper tool is used to hold
the fl ywheel in order to remove the clutch, structural damage
to the fl ywheel could occur and could subsequently cause the
fl ywheel to burst.)

WARNING

○ Never modify the unit/machine in any way. Do not use your unit/

machine for any job except that for which it is intended.

○ Never use chain saw without any safety equipment or that has

faulty safety equipment. It could result in serious personal injury.

○ Using guide bar/chain other than

manufacturer which are not approved, could result in a high risk
of personal accidents or injury.

Fuel safety

○ Mix and pour fuel outdoors and where there are no sparks or

fl ames.

○ Use a container approved for fuel.
○ Do not smoke or allow smoking near fuel or

while using the unit/machine.

○ Wipe up all fuel spills before starting engine.
○ Move at least 3 m away from fueling site before starting engine.
○ Stop engine and let it cool for a few minutes before removing fuel

tank cap.

○ Empty the fuel tank before storing

recommended that the fuel be emptied after each use. If fuel is
left in the tank, store so fuel will not leak.

○ Store unit/machine and fuel in area where fuel vapors cannot

reach sparks or open fl ames from water heaters, electric motors
or switches, furnaces, etc.

WARNING

Fuel is easy to ignite or get explo sion or inhale fumes, so that pay

special attention when handling or fi lling fuel.

Cutting safety

○ Do not cut any material oth er than wo od or wooden objects.
○ For respiratory protection, wear an aerosol protection mask

when cutting the wood after insecticide has

○ Keep others in cluding children, animals, by standers and helpers

outside the hazard zone. Stop the engine immediately if yo u are
approached.

○ Hold the unit/machine fi rmly with the right hand on the rear

handle and the left hand on the front handle.

○ Keep fi rm footing and balance. Do not
○ Keep all parts of your body away from the muffl er and cutting

attachment when the engine is running.

○ Keep Bar/Chain below waist level.
○ Before felling a tree, the operator must be accustomed to the

sawing techniques of the chain saw.

○ Be sure to pre-plan a safe
○ While cutting, hold the unit/machine fi rmly with both hands with

thumb fi rmly locked around front handle, and stand with feet well
balanced and your body balanced.

○ Stand to the side of the saw when cutting - never directly behind

it.

○ Always keep the spiked

chain may suddenly be drawn into a tree, if so equipped.

○ When completing a cut, be ready to hold up the units as it breaks

into clear, so it will not fol low through and cut yo ur legs, feet or
body, or contact an

○ Be alert again st kickback (when saw kicks up and back at

operator). Never cut with the nose of the bar.

○ When relocating to a new work area, be sure to shut off the

machine and ensure that all cut ting at tachments are stopped.

○ Never place the machine on the
○ Always ensure that the engine is shut off and any cutting

attachments have completely stopped before clearing debris or
removing grass from the cutting attachment.

○ Always carry a fi rst-aid kit when operating any power equipment.

exit from a failing tree.

bumper face to a tree, because the

obstruction.

ground when running.

if improper tool s are

recommended by the

the unit/machine or

the unit/machine. It is

been applied.

over-reach.

4

○ Never star t or run the engine inside a closed room

and/or near the infl ammable liquid. Breathing exhaust fumes
can kill.

Maintenance safety

○ Maintain the unit/machine according to recommended

procedures.

○ Disconnect the spark plug before performing maintenance

except for carburetor adjustments.

○ Keep others away when making carburetor adjustments.
○ Use only genuine HITACHI replacement parts as recommended

the manufacturer.

by

CAUTION

Do not disassemble the recoil starter. You may get a possibilit y

of personal injury with recoil spring.

WARNING

Improper maintenance could result in serious engine damage or

in serious personal injury.

Tra ns po rt and storage

○ Carry the unit/machine by hand with the engine stopped and the

muffl er away from your body.

○ Allow the engine to cool, empty the fuel tank, and secure the

unit/machine before storing or

○ Empty the fuel tank before storing the unit/machine. It is

recommended that the fuel be emptied after each use. If fuel is
left in the tank, store so fuel will not leak.

○ Store unit /machine out of the reach of children.
○ Clean and maintain the unit
○ Make sure stop switch is off when transporting or storing.
○ When transporting or storage, cover chain with guide bar cover.

If situations occur which are not covered in this manual, take care and
use common sense. Contact HITACHI dealer if you
Pay special attention to statements preceded by the following words:

WARNING

Indicates a strong possibility of severe personal injury or loss of

life, if instructions are not followed.

CAUTION

Indicates a possibility of personal injury or equipment damage, if

instructions are not followed.

NOTE

Helpful information for correct function and use.

WARNING

KICKBACK DANGER (Fig. 1)

One of the most severe dangers when work ing with a chain saw is
the possibility of kickback. Kickback may occur when the upper tip
of the guide bar touches an object, or when the woo d closes in and
pinches the saw chain in the cut. Tip contact
cause a lightning fast reverse reaction, kicking the guide bar up and
back toward yo u. Pinching the saw chain along the top of the guide
bar may also push the guide bar rapidly back towar ds you. Either of
these reactions may cause you to lose control
result in serious personal injury. Even though your saw has safety
built into its design, you should not rely on these safety featu res
exclusive ly. Know where your bar tip is at all times. Kickback does
occur if you allow the kickback zone (1) of the bar
Do not use that area. Kickback from pinching is caused by a cut
closing and pinching the upper side of the guide bar. Study your cut
and make sure it will open as you cut through. Maintain control when
the engine is running by always keeping
your right hand on the rear handle, your left hand on the front handle
and your thumbs and fi ngers encircling the handles. Always hold the
saw with both hands during operation and cut at high engine speed.
Follow manufacturer's sharpening and maintenance instructions

the saw chain. The lack of this maintenance may increase the

for
possibility of kickback.

transporting in a vehicle.

carefully and store it in a dry place.

of the saw which could

a fi rm grip on the saw with

Fig. 1

or building

need assistance.

in some cases may

to touch an object.

1

English

SPECIFICATIONS

○ Code “CS” of model name means “Chain saw”

Typ e of equipment Chain saw, portable

Engine Size (cm

Spark Plug NGK BPMR-7A

Fuel Ta nk Capacity (cm

Chain Oil Tan k Capacity (cm

Dry Weight (kg)
(Without guide bar and chain)

3

) 50.1

3

)530

3

)270

Chain pitch (mm) 8.26

Chain gauge (mm) 1.2 7

Sound pressure level LpA (d B (A)) by ISO 22868

Equivalent
Uncertainty

Sound power level Lw A (dB (A)) by ISO 22868
Measured

Sound power level Lw A (dB (A)) by 2000/14/EC
Measured
Guaranteed

Vibration level (m/s
Front handle
Rear handle
Uncertainty

2

) by ISO 22867

Guide bar length (mm) 400 450 500

Typ e of chain

Max. engine power
by ISO 7293 (kW)

Max. engine speed (min

Idle engine speed (min

Specifi c fuel consumption at maximum engine
power (g/kWh)

-1

)13500

-1

) 3000

Max. chain speed (m/sec) 26.0

Sprocket (numbe r of teeth) 7

NOTE: Eq uivalent noise level/vibration levels are calculated as the time-weighted energy tot al for noise/vibration levels under various

working conditions with the following time distribution: 1/3 idle, 1/3 full, 1/3 racing speed.
*Al l data subject to change without notice.

Model CS51EA (40S) CS51E A (45S) CS51E A (50S)

5.1

104

1

Uncertainty

3.3

2.7

0.8

95VPX

(Oreg on)

113

114
117

3.3

2.7

0.8

2

2.5

439

3.3

2.7

0.8

20BPX

(Oreg on)

ASSEMBLY PROCEDURES

WARNING

Never try to start engine without side case, bar and chain

securely fastened.

1. Pull the front hand guard (2) toward the front handle to check that
the chain brake is disengaged. (Fig. 2)

2

Fig. 2

2. Remove guide bar clamp nuts (3). Remove the side case (4) .
(Fig. 3)

4

3

Fig. 3

5