Zenoah GZ400 User manual

GZ400
GB-1
G
B
GZ400
OWNER’S MANUAL
CHAIN SAW
G
B
X372340052(801)

GZ400
GB-2
EXPLANATION OF SYMBOLS AND SAFETY WARNINGS
Read operator's instruction
book before operating this
machine.
Wear head, eye and ear
protection.
Warning! Danger of
kickback.
Wear non-slip, heavy-duty
protective gloves when handling
the chain saw.
Read, understand and
follow all warnings.
APPROVAL NUMBER OF CE EXHAUST EMISSION REGULATION (2002/88/EC)
e1*97/68SH2-IIA*2004/26*0405*00
Do not operate the saw
properly with both hands.
Avoid bar nose contact. Hold and operate the saw
properly with both hands.
WARNING!!!
RISK OF DAMAGING HEARING
Wear head, eye and ear protection.
MODEL SOUND LEVEL VIBRATION LEVEL
LwA LpA Front handle
GZ400
ISO 22868 ISO 22867
Rear handle
103 dB(A) 112 dB(A) 113 dB(A) 6.4 m/s27.0 m/s2
LwA
2000/14/EC
Important!
It is essential that read the instructions in this manual before mounting
and operating this machine.

GZ400
GB-3
G
B
Contents
1. For Safe Operation ................................................................... 4
2. Explanation of Symbols on the Machine .................................. 6
3. Installing Guide Bar and Saw Chain ......................................... 7
4. Fuel and Chain Oil .................................................................... 8
5. Operating the Engine ............................................................... 9
6. Sawing .................................................................................... 11
7. Maintenance ........................................................................... 12
8. Maintenance of Saw Chain and Guide Bar ............................ 13
9. Storage ................................................................................... 14
10. Troubleshooting Guide ........................................................... 14
11. Specifications ......................................................................... 15
Masahiko GOUDA
General Manager, Quality Assurance Department
Jan. 1st 2008
Signed in Saitama, Japan
CONFORMS TO REQUIREMENTS OF THE MODIFIED MACHINES DIRECTIVE
(Directive 98/37/EC), EN ISO 11681-1:2004; EN ISO 22868:2005; EN ISO
22867:2004; EN 55012:2002; EN ISO 14982:1998 AND TO THE NATIONAL
REGULATIONS GOVERNING ITS TRANSPOSITION ABROAD: AND
THAT IT HAS BEEN ISSUED WITH A, CE CERTIFICATE, BY INTERTEK
DENTSCHLAND GmbH.
The engineering type licence no. (issued by Intertek Deutschland GmbH is
07SHW0982-01.
Measured sound power level:112bB(A)
Guaranteed sound power level; 113bB(A)
Maintenance of technical documentation:
DECLARATION OF CONFORMITY TO MACHINES DIRECTIVE
(Directive 98/37/EC, 2002/83/EC, 89/336/EEC) ,2000/14/EC
and to the regulations governing transposition
Internal contorol production
MANUFACTURER : Husqvarna Zenoah Co., Ltd.
No. 9, 1-Chome
MINAMIDAI, KAWAGOE City
SAITAMA, JAPAN
DECLARES THAT THE DESIGN OF THE MACHINE DESCRIBED BELOW:
Model : GZ400
Serial no. : 0801000001 and up
Make : Husqvarna Zenoah Co., Ltd.

GZ400
GB-4
1. For safe operation
1. Never operate a chain saw when
you are fatigued, ill, or upset, or
under the influence of medica-
tion that may make you drowsy,
or if you are under the influence
of alcohol or drugs.
2. Use safety footwear, snug fitting
clothing and eye, hearing and
head protection devices.
Use the vibration-proof glove.
3. Keep the saw chain sharp and
the saw, including the AV system,
well maintained. A dull chain will
increase cutting time, and press-
ing a dull chain through wood will
increase the vibrations transmit-
ted to your hands. A saw with
loose components or with dam-
aged or worn AV buffers will also
tend to have higher vibration lev-
els.
4. All the above mentioned precau-
tions do not guarantee that you
will not sustain whitefinger dis-
ease or carpal tunnel syndrome.
Therefore, continual and regular
users should monitor closely the
condition of their hands and fin-
gers.
If any of the above symptoms ap-
pear, seek medical advice imme-
diately.
5. Always use caution when han-
dling fuel. Wipe up all spills and
then move the chain saw at least
3 m from the fueling point before
starting the engine.
6. Eliminate all sources of sparks or
flame (i.e. smoking, open flames,
or work that can cause sparks)
in the areas where fuel is mixed,
poured, or stored.
7. Do not smoke while handling fuel
or while operating the chain saw.
8. Do not allow other persons to be
near the chain saw when start-
ing or cutting. Keep bystanders
and animals out of the work area.
Children, pets and bystanders
should be a minimum of 10 m
away when you start or operate
the chain saw.
9. Never start cutting until you have
a clear work area, secure foot-
ing, and a planned retreat path
from the falling tree.
10. Always hold the chain saw firmly
with both hands when the engine
is running. Use a firm grip with
thumb and fingers encircling the
chain saw handles.
11. Keep all parts of your body away
from the saw chain when the en-
gine is running.
12. Before you start the engine,
make sure the saw chain is not
contacting anything.
13. Always carry the chain saw with
the engine stopped, the guide
bar and saw chain to the rear,
and the muffler away from your
body.
14. Always inspect the chain saw be-
fore each use for worn, Ioose, or
damaged parts. Never operate
a chain saw that is damaged, im-
properly adjusted, or is not com-
pletely and securely assembled.
Be sure that the saw chain stops
moving when the throttle control
trigger is released.
15. All chain saw service, other than
the items listed in the Owner’s
Manual, should be performed by
competent chain saw service
personnel. (E.g., if improper tools
are used to remove the flywheel,
or if an improper tool is used to
hold the flywheel in order to re-
move the clutch, structural dam-
age to the flywheel could occur

GZ400
GB-5
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B
which could subsequently cause
the flywheel to disintegrate.)
16. Always shut off the engine be-
fore setting it down.
17. Use extreme caution when cut-
ting small size brush and sap-
lings because slender material
may catch the saw chain and be
whipped toward you or pull you
off balance.
18. When cutting a limb that is un-
der tension, be alert for spring-
back so that you will not be
struck when the tension in the
wood fibers is released.
19. Never cut in high wind, bad
weather, when visibility is poor or
in very high or low temperatures.
Always check the tree for dead
branches which could fall during
the felling operation.
20. Keep the handles dry, clean and
free of oil or fuel mixture.
21. Operate the chain saw only in
well ventilated areas. Never start
or run the engine inside a closed
room or building. Exhaust fumes
contain dangerous carbon mon-
oxide.
22. Do not operate the chain saw in
a tree unless specially trained to
do so.
23. Guard against kickback. Kick-
back is the upward motion of the
guide bar which occurs when the
saw chain at the nose of the
guide bar contacts an object.
Kickback can lead to dangerous
loss of control of the chain saw.
24. When transporting your chain
saw, make sure the appropriate
guide bar scabbard is in place.
KICKBACK SAFETY PRECAU-
TIONS FOR CHAIN SAW USERS
WARNING
• Kickback may occur when the
nose or tip of the guide bar
touches an object, or when the
wood closes in and pinches the
saw chain in the cut. Tip contact
in some cases may cause a light-
ning fast reverse reaction,kicking
the guide bar up and back to-
wards the operator. Pinching the
saw chain along the top of the
guide bar may push the guide
bar rapidly back towards the op-
erator. Either of these reactions
may cause you to Iose control of
the saw, which could result in
serious personal injury.
• Do not rely exclusively on the
safety devices built into your saw.
As a chain saw user you should
take several steps to keep cut-
ting jobs free from accident or
injury.
(1) With a basic understanding of
kickback you can reduce or
eliminate the element of surprise.
Sudden surprise contributes to
accidents.
(2) Keep a good grip on the saw with
both hands, the right hand on the
rear handle, and the left hand on
the front handle, when the engine
is running. Use a firm grip with
thumbs and fingers encircling
the chain saw handles. A firm
grip will help you reduce kick-
back and maintain control of the
saw.
(3) Make certain that the area in
which you are cutting is free from
obstructions. Do not let the nose
of the guide bar contact a log,
branch, or any other obstruction
which could be hit while you are
operating the saw.
(4) Cut at high engine speeds.
(5) Do not overreach or cut above
shoulder height.
(6) Follow the manufacturer’s sharp-
ening and maintenance instruc-
tions for the saw chain.
(7) Only use replacement bars and
chains specified by the manufac-
turer or the equivalent.

GZ400
GB-6
2. Explanation of Symbols on the Machine
The port to refuel “MIX GASOLINE”
Position: Fuel cap
The port to top up chain oil
Position: Oil cap
Setting the switch to the “O” position, the engine stops immediately.
Position: Rear-left of the unit
Starting the engine. If you pull out the choke knob (at the back-right of
the rear handle) to the point of the arrow, you can set the starting mode
as follows:
•
HALF CHOKE – starting mode when the engine is warm.
• FULL CHOKE – starting mode when the engine is cold.
Position: Upper-right of the aircleaner cover
The screw under the “H” stamp is The High-speed adjustment screw.
The screw under the “L” stamp is The Slow-speed adjustment screw.
The screw at the left of the “T” stamp is the Idle adjustment screw.
Position: Left side of the rear handle
Shows the directions that the chain brake is released (white arrow) and
activated (black arrow).
Position: Front of the chain cover
For safe operation and maintenance, symbols are carved in relief on the
machine.
According to these indications, please be careful not to make any mistake.

GZ400
GB-7
G
B
4. Fit the chain cover to the power unit and fasten the
nuts to finger tightness.
5. While holding up the tip of the bar, adjust the chain
tension by turning the tensioner screw until the tie
straps just touch the bottom side of the bar rail.
6. Tighten the nuts securely with the bar tip held up
(12 ~ 15 N·m). Then check the chain for smooth ro-
tation and proper tension while moving it by hand. If
necessary, readjust with the chain cover loose.
7. Tighten the tensioner screw.
Note: A new chain will expand its length in the beginning of use.
Check and readjust the tension frequently as a loose chain can
easily derail or cause rapid wear of itseif and the guide bar.
3. Installing Guide Bar and Saw Chain
A standard saw unit package contains the items as illustrated.
Open the box and install the guide bar and the saw
chain on the power unit as follows:
The saw chain has very sharp edges. Use
thick protective gloves for safety.
1. Pull the guard towards the front handle to check that
the chain brake is not engaged.
2. Loosen the nuts and remove the chain cover.
3. Gear the chain to the sprocket and, while fitting the
saw chain around the guide bar, mount the guide
bar to the power unit. Adjust the position of the chain
tensioner.
Note: Pay attention to the correct direction of the saw chain.
Tensioner nut
Chain cover
Moving direction
Tighten
Tensioner screw
Loosen
Lift up
Power unit
Bar protector
Guide bar
Saw chain
Plug wrench

GZ400
GB-8
4. Fuel and Chain Oil
■ FUEL
WARNING
•Gasoline is very flammable. Avoid smoking or
bringing any flame or sparks near fuel. Make sure
to stop the engine and allow it cool before refuel-
ing the unit. Select outdoor bare ground for fuel-
ing and move at least 3 m (10 ft) away from the
fueling point before starting the engine.
4. Pour in the rest of gasoline and agitate again for at
least one minute. As some oils may be difficult to
agitate depending on oil ingredients, sufficient agi-
tation is necessary for the engine to last long. Be
careful that, if the agitation is insufficient, there is an
increased danger of early piston seizing due to ab-
normally lean mixture.
5. Put a clear indication on the outside of the container
to avoid mixing up with gasoline or other contain-
ers.
6. Indicate the contents on outside of container for easy
identification.
■ FUELING THE UNIT
1. Untwist and remove the fuel cap. Rest the cap on a
dustless place.
2. Put fuel into the fuel tank to 80% of the full capacity.
3. Fasten the fuel cap securely and wipe up any fuel
spillage around the unit.
WARNING
1. Select flat and bare ground for fueling.
2. Move at least 10 feet (3 meters) away from the fuel-
ing point before starting the engine.
3. Stop the engine before refueling the unit. At that time,
be sure to sufficiently agitate the mixed gasoline in
the container.
■ FOR YOUR ENGINE LIFE, AVOID:
1. FUEL WITH NO OIL (RAW GASOLINE) – It will cause
severe damage to the internal engine parts very
quickly.
2.
GASOHOL – It can cause deterioration of rubber and/
or plastic parts and disruption of engine lubrication.
3. OIL FOR 4-CYCLE ENGINE USE – It can cause spark
plug fouling, exhaust port blocking, or piston ring
sticking.
4. Mixed fuels which have been left unused for a
period of one month or more may clog the carbu-
retor and result in the engine failing to operate prop-
erly.
5. In the case of storing the product for a long period
of time, clean the fuel tank after rendering it empty.
Next, activate the engine and empty the carburetor
of the composite fuel.
6. In the case of scrapping the used mixed oil con-
tainer, scrap it only at an authorized repository site.
Note: As for details of quality assurance, read the description in
the section Limited Warranty carefully. Moreover, normal wear and
change in product with no functional influence are not covered by
the warranty. Also, be careful that, if the usage in the instruction
manual is not observed as to the mixed gasoline, etc. described
therein, it may not be covered by the warranty.
■ CHAIN OIL
Use special chain saw oil or synthetic 2-stroke oil.
Note: Do not use wasted or regenerated oil that can cause damage
to the oil pump.
• The Zenoah engines are lubricated by oil specially
formulated for air-cooled 2-cycle gasoline engine use.
If Zenoah oil is not available, use an anti-oxidant added
quality oil expressly labeled for air-cooled 2-cycle
engine use (JASO FC GRADE OIL or ISO EGC
GRADE).
• Do not use BIA or TCW (2-stroke water-cooling type)
mixed oil.
■RECOMMENDED MIXING RATIO
GASOLINE 50 : OIL 1
(when using ZENOAH genuine oil)
•Exhaust emission are controlled by the funda-
mental engine parameters and components (eq.,
carburation, ignition timing and port timing) with-
out addition of any major hardware or the intro-
duction of an inert material during combustion.
• These engines are certified to operate on unleaded
gasoline.
• Make sure to use gasoline with a minimum octane
number of 89RON (USA/Canada: 87AL).
• If you use a gasoline of a lower octane value than
prescribed, there is a danger that the engine tem-
perature may rise and an engine problem such as
piston seizing may consequently occur.
• Unleaded gasoline is recommended to reduce the
contamination of the air for the sake of your health
and the environment.
• Poor quality gasolines or oils may damage sealing
rings, fuel lines or fuel tank of the engine.
■ HOW TO MIX FUEL
• Pay attention to agitation.
1. Measure out the quantities of gasoline and oil to be
mixed.
2. Put some of the gasoline into a clean, approved fuel
container.
3. Pour in all of the oil and agitate well.

GZ400
GB-9
G
B
6. Push the choke knob to HALF CHOKE position.
7. Pull starter grip until engine runs.
Note: Allow the saw to run in this position 15~30 seconds, depending
upon the temperature.
8. Push the choke knob in to the RUN position.
Note: When restarting immediately after stopping the engine, set the
Choke knob in the HALF CHOKE position (choke open and throttle lever
in the starting position).
Keep clear of the saw chain as it will start
rotatIng upon starting of engine.
■ CHECKING THE OIL SUPPLY
Make sure to set up the bar and the chain when
checking the oil supply.
If not, the rotating parts may be exposed. It is very
dangerous.
After starting the engine, run the chain at medium speed
and see if chain oil is scattered off as shown in the fig-
ure.
Note: The oil tank should become nearly empty by the time fuel is used
up. Be sure to refill the oil tank every time when refueling the saw.
■ ADJUSTING THE CARBURETOR
The carburetor on your unit has been factory adjusted,
but may require fine tuning due to a change in operat-
ing conditions.
Before adjusting the carburetor, make sure that the pro-
vided air/fuel filters are clean and fresh and the fuel prop-
erly mixed.
When adjusting, take the following steps:
Note: Be sure to adjust the carburetor with the bar chain attached.
It is very dangerous to run a chainsaw that mounts
broken parts or lacks any parts.
Before starting engine, make sure that all the parts
including bar and chain are installed properly.
■ STARTING THE ENGINE
1. Fill fuel and chain oil tanks respectively, and tighten the
caps securely.
2. Set the switch to “I” position.
3. Continuously push the primer until fuel comes in the bulb.
4. Pull the choke knob all the way out to FULL CHOKE po-
sition.
5. While holding the saw unit securely on the ground, pull
the starter grip until the engine attempts to start, but no
more than 5 times.
Do not start the engine while the chain saw hangs
in one hand. The saw chain may touch your body.
This in very dangerous.
L needle H needle
Idle adjusting
screw
5. Operating the Engine
Chain oil
Fuel
Chain oil
Switch
Throttle lever
Throttle
interlock
Primer
Choke knob
(FULL CHOKE
Position)
RUN
HALF CHOKE
FULL CHOKE

GZ400
GB-10
Fine adjustment of the idling speed T
Adjust the idle speed with the T-screw. If it is necessary to
readjust, turn the T-screw clockwise while the engine is run-
ning, until the chain starts to rotate. Then turn counter-clock-
wise until the chain stops. A correctly adjusted idle speed set-
ting occurs when the engine runs smoothly in every position. It
should also be good margin to the rpm when the chain starts
to rotate.
Contact your servicing dealer, if the idle speed set-
ting cannot be adjusted so that the chain stops.
Do not use the chain saw until it has been properly
adjusted or repaired.
■ CHAIN BRAKE
This machine is equipped with an automatic brake to stop saw
chain rotation upon occurrence of kickback during saw cut-
ting. The brake is automatically operated by inertial force, which
acts on the weight fitted inside the front guard.
This brake can also be operated manually with the front guard
turned down to the guide bar.
To release the brake, pull up the front guard toward the front
handle till a “click” sound is heard.
[Caution]
Be sure to confirm brake operation during daily inspection.
How to confirm:
1) Turn off the engine.
2) Holding the chain saw horizontally, release your hand from
the front handle, hit the tip of the guide bar to a stump or a
piece of wood, and confirm brake operation. Operating
level varies by bar size.
In case the brake is not effective, ask our dealer for inspection
and repairs.
If the engine keeps rotating at high speed with the brake en-
gaged, the clutch will overheat causing trouble.
When the brake engages during operation, immediately re-
lease the throttle lever to stop the engine.
■ STOPPING THE ENGINE
1. Release the throttle lever to allow the engine to idle for a
few minutes.
2. Set the switch to the “O” (STOP) position.
[Important]
Do not put the chain saw on the ground when the chain is still moving.
For additional safety, set the chain brake when the saw is not in use.
In the event that the ignition switch will not stop the saw, pull
the choke knob out to the fully extended position "FULL
CHOKE" and engage chain brake to stop the engine. If the
ignition switch will not stop the saw when set to the "STOP"
position, have the ignition switch repaired before using the chain
saw again to prevent unsafe conditions or serious injury.
Note: When you are finished using the saw, always re lieve tank pressure
by loosening, then retightening, the chain oil and fuel mix caps. Allow
the engine to cool before storing.
Carburetor anti-freeze mechanism
Operating chain saws in temperatures of 0 – 5°C at times of high
humidity may result in ice forming within the carburetor, and this in
turn may cause the output power of the engine to be reduced or for
the engine to fail to operate smoothly.
This product has accordingly been designed with a ventilation hatch on
the right side of the surface of the cylinder cover to allow warm air to be
supplied to the engine and to thereby prevent icing from occurring.
Under normal circumstances the product should be used in the nor-
mal operating mode, i.e., in the mode to which it is set at the time of
shipment. However when the possibility exists that icing may occur,
the unit should be set to operate in the anti-freeze mode before use.
Continuing to use the product in the anti-freeze
mode even when temperatures have risen and re-
turned to normal, may result in the engine failing to
start properly or in the engine failing to operate at
its normal speed, and for this reason you should
always be sure to return the unit to the normal oper-
ating mode if there is no danger of icing occurring.
■ HOW TO SWITCH BETWEEN OPERATING MODES
1. Flip the engine switch to turn off the engine.
2. Remove the cover to the air filter, remove the air filter, and
then remove the choke knob from the cylinder cover.
3. Loosen the screws holding the cylinder cover in place (i.e.,
the three screws on the inside and the one screw on the
outside of the cover), and then remove the cylinder cover.
4. Press with your finger down on the icing cap located on the
right-hand side of the cylinder cover to remove the icing cap.
5. Adjust the icing cap so that the “snow” mark faces upwards
and then return it to its original position in the cylinder cover.
6. Fix the cylinder cover back into its original position, and
then fix all other parts back into their proper positions.
Switch
Choke knob
Cylinder cover
Icing cap
T-screw
Normal operating mode Anti-freeze mode
Cylinder cover
“Sunshine” mark “Snow” mark

GZ400
GB-11
G
B
6. Sawing
• Before proceeding to your job,
read the section “For Safe
Operation”. It is recommended
to first practice sawing easy
logs. This also helps you get
accustomed to your unit.
• Always follow the safety regu-
lations. The chain saw must
only be used for cutting wood.
It is forbidden to cut other
types of material. Vibrations
and kickback vary with differ-
ent materials and the require-
ments of the safety regulations
would not be respected. Do
not use the chain saw as a le-
ver for lifting, moving or split-
ting objects. Do not lock it over
fixed stands. It is forbidden to
hitch tools or applications to
the PTO other than those
specified by the manufacturer.
• It is not necessary to force the saw into the
cut. Apply only light pressure while running the
engine at full throttle.
• When the saw chain is caught in the cut, do
not attempt to pull it out by force, but use a
wedge or a lever to open the way.
■ GUARD AGAINST KICKBACK
• This saw is equipped with a chain
brake that will stop the chain in the
event of kickback if operating prop-
erly. You must check the chain brake
operation before each usage by run-
ning the saw at full the throttle for I -
2 seconds and pushing the front
hand guard forward. The chain
should stop immediately with the en-
gine at full speed. If the chain is slow
to stop or does not stop, replace the
brake band and clutch drum before
use.
• It is extremely important that the
chain brake be checked for proper
operation before each use and that
the chain be sharp in order to main-
tain the kickback safety level of this
saw. Removal of the safety devices,
inadequate maintenance, or incor-
rect replacement of the bar or chain
may increase the risk ot serious per-
sonal injury due to kickback.
■ FELLING A TREE
1. Decide the felling direction considering the wind,
lean of the tree, location of heavy branches, ease of
completing the task after felling and other factors.
2. While clearing the area around the tree, arrange a
good foothold and retreat path.
3. Make a notch cut one-third of the way into the tree
on the felling side.
4. Make a felling cut from the opposite side of the notch
and at a level slightly higher than the bottom of the
notch.
When you fell a tree, be sure to warn neigh-
boring workers of the danger.
Bucking and Limbing
• Always ensure your foothold. Do not stand
on the log.
• Be alert to the rolling over of a cut log. Es-
pecially when working on a slope, stand
on the uphill side of the log.
• Follow the instructions in “For Safe Opera-
tion” to avoid kickback of the saw.
Before starting work, check the direction of bending
force inside the log to be cut. Always finish cutting from
the opposite side of the bending direction to prevent
the guide bar from being caught in the cut.
Notch cut Felling cut
Felling direction

GZ400
GB-12
3. Guide bar
When the guide bar is dismounted, remove sawdust in the bar
groove and the oiling port.
Grease the nose sprocket from the feeding port on the tip of
the bar.
4. Others
Check for fuel leakage and loose fastenings and damage to
major parts, especially handle joints and guide bar mounting.
If any defects are found, make sure to have them repaired
before operating the saw again.
■ PERIODICAL SERVICE POINTS
1. Air cooling system
Dust clogging around the cooling system and the cylinder fins
will cause overheating of the engine. Periodically check and
clean the cooling system and the cylinder fins with a brush
after removing the cylinder cover, the air cleaner and the recoil
case. When installing the cylinder cover and the cooling sys-
tem, make sure that switch wires and grommets are positioned
correctly in place.
7. Maintenance
Oiling port
Sprocket
Oiling port
Before cleaning, the inspecting or repairing the unit,
make sure that engine has stopped and is cool.
Disconnect the spark plug to prevent accidental
starting.
■ MAINTENANCE AFTER EACH USE
1. Air filter
Dust on the cleaner surface can be removed by tapping a
corner of the cleaner against a hard surface. To clean dirt in
the meshes, split the cleaner into halves and brush in gaso-
line. When using compressed air, blow from the inside.
To assemble the cleaner halves, press the rim until it clicks.
Note: When installing the main filter, make sure that the grooves on the
filter edge are correctly fit with the projections on the cylinder cover.
2. Oiling port
Dismount the guide bar and check the oiling port for clogging.
A log lying on the ground
Saw down halfway, then roll the log over and cut from
the opposite side.
A log hanging off the ground
In area A, saw up from the bottom one-third and finish
by sawing down from the top. In area B, saw down from
the top one-third and finish by sawing up from the bot-
tom.
Cutting the limbs of Fallen Tree
First check to which side the limb is bent. Then make
the initial cut from the bent side and finish by sawing
from the opposite side.
Be alert to the springing back of a cut limb.
Pruning of Standing Tree
Cut up from the bottom, finish down from the top.
• Do not use an unstable foothold or ladder.
• Do not overreach.
• Do not cut above shoulder height.
• Always use both your hands to hold the
saw.
Grease port
Fan cover
Fan
Cylinder fins
Cylinder cover
Recoil case

GZ400
GB-13
G
B
4. Fuel filter
(a) Using a wire hook, take out the filter from the filler port.
(b) Disassemble the filter and wash with gasoline, or replace
with a new one if needed.
Note:
• After removing the filter, use a pinch to hold the end of the suction pipe.
• When assembling the filter, take care not to allow filter fibers or dust
inside the suction pipe.
5. Spark plug
Clean the electrodes with a wire brush and reset the gap to
0.65 mm as necessary.
6. Sprocket
Check for cracks and for excessive wear interfering with the chain
drive. If the wear is considerable, replace it with new one. Never fit a
new chain on a worn sprocket, or a worn chain on a new sprocket.
After each cutter has been filed, check the depth gauge and
file it to the proper level as illustrated.
8. Maintenance of Saw Chain and Guide Bar
Appropriate gauge checker
Make the shoulder round
Depth gauge standard
■ Saw Chain
It is very important for smooth and safe operation
to always keep the cutters sharp.
The cutters need to be sharpened when:
• Sawdust becomes powder-like.
• You need extra force to saw in.
• The cut path does not go straight.
• Vibration increases.
• Fuel consumption increases.
Cutter setting standards:
Be sure to wear safety gloves.
Before filing:
• Make sure the saw chain is held securely.
• Make sure the engine is stopped.
• Use a round file of proper size for the chain.
Chain type: Carlton N1C-BL-M-57E-SK
File size: 5/32 in (1.6 mm)
Place the file on the cutter and push straight forward. Keep the
file position as illustrated.
.025″(0.64 mm)
Muffler exhaust vent
Cylinder exhaust port
Fuel filter
• Champion RZ7C
Spark arrester
Note: Be sure to block the air intake hole.
2. Spark arrester
The muffler is equipped with a spark arrester to prevent red hot
carbon from flying out of the exhaust outlet. Periodically check
and clean as necessary with a wire brush after removing two
muffler cover nuts and one screw.
Note: Never use a muffler if the spark arrester is missing or defective.
3. Exhaust port
Remove the muffler, insert a screwdriver into the vent, and wipe
away any carbon buildup after every 100 hours of use. Wipe
away any carbon buildup on the muffler exhaust vent and the
cylinder exhaust port at the same time.

GZ400
GB-14
10. Troubleshooting Guide
Case 1. Starting failure
Make sure the icing prevention system is not work-
ing.
Check fuel for water or
substandard mixture.
Replace with proper
fuel.
Check for engine
flooding.
Check spark ignition.
Remove and dry the
spark plug.
Then pull the starter
again with no choke.
Replace with a new
plug.
Case 2. Lack of power/Poor acceleration/
Rough idling
Case 3. Oil does not come out
Check fauel for water
or substandard mix-
ture.
Check air filter and fuel
filter for clogging.
Check carburetor for
inadequate adjust-
ment.
If the unit seems to need further service, please consult
with an authorized service shop in your area.
Replace with proper
fuel.
Clean.
Readjust speed
needles.
Check oil for substan-
dard quality.
Check oil passage and
ports for clogging.
Replace.
Clean.
a
d
d
a
a
d
d
a
a
a
d
a
a
Be sure to round off the front edge to reduce the
chance of kickback or tie-strap breakage.
Make sure every cutter has the same length and edge angles
as illustrated.
■ Guide Bar
• Reverse the bar occasionally to prevent partial wear.
• The bar rail should always be square. Check for wear of
the bar rail. Apply a ruler to the bar and the outside of a
cutter. If a gap is observed between them, the rail is nor-
mal. Otherwise, the bar rail is worn. Such a bar needs to
be corrected or replaced.
Cutter length
Filing angle
Side plate angle
Ruler
Gap
No gap
Chain tilts
WARNING:
This saw is equipped with one of the following low kickback
bar/chain combinations:
Zenoah Part Number
Saw Model Bar Size Guide Bar Saw Chain
GZ400 16” 16-10-N1-MHC UNB G N1C-BL-M-57E SK
9. Storage
Aged fuel is one of major causes of engine starting failure. Before storing the unit, empty the fuel tank and run the engine until it
uses all the fuel left in the fuel line and the carburetor. Store the unit indoor taking necessary measures for rust prevention.

GZ400
GB-15
G
B
11. Specifications
Power unit:
Displacement (cm3): ............................................. 40.1
Fuel: ................ Mixture (Gasoline 50 : Two-cycle oil 1)
(when using ZENOAH genuine oil)
Fuel tank capacity (cm3): ....................................... 310
Chain oil: ..................................... special chain saw oil
or synthetic 2-stroke oil
Oil tank capacity (cm3): .......................................... 210
Carburetor: .................... Diaphragm type (ZAMA C1Q)
lgnition system: ..................................... Pointless (CDl)
Spark plug:......................................... Champion RZ7C
Oil feeding system: ............................ Automatic pump
Power ........................................ 1.77/10,000 (kw/min-1)
Max speed ............................................. 12,000 (min-1)
Idle speed ................................................ 2,700 (min-1)
Sprocket (Teeth x Pitch): ................................ 6T x 3/8″
Limited warranty
Should any failure occur on the product under normal
operating conditions within the applicable warranty pe-
riod, the failed part will be replaced or repaired free of
charge by a ZENOAH authorized dealer.
WARRANTY PERIOD: 1 year (6 months if used profes-
sionally, and 30 days if used for rental purpose) from
the date of initial purchase.
THE PURCHASER SHALL BEAR COSTS OF TRANS-
PORTING THE UNIT TO AND FROM THE ZENOAH
DEALER.
THE PURCHASER SHALL NOT BE CHARGED FOR DI-
AGNOSTIC LABOR WHICH LEADS TO THE DETERMI-
NATION THAT A WARRANTED PART IS DEFECTIVE, IF
THE DIAGNOSTIC WORK IS PERFORMED AT THE
ZENOAH DEALER.
THE PURCHASER OR OWNER IS RESPONSIBLE FOR
THE PERFORMANCE OF THE REQUIRED MAINTE-
NANCE AS DEFINED BY THE MANUFACTURER IN THE
OWNER/OPERATOR MANUAL.
ANY WARRANTED PART WHICH IS NOT SCHEDULED
FOR REPLACEMENT AS REQUIRED MAINTENANCE,
OR WHICH IS SCHEDULED ONLY FOR REGULAR IN-
SPECTION TO THE EFFECT OF REPAIR OR “REPLACE
AS NECESSARY” SHALL BE WARRANTED FOR THE
WARRANTY PERIOD. ANY WARRANTED PART WHICH
IS SCHEDULED FOR REPLACEMENT AS REQUIRED
MAINTENANCE SHALL BE WARRANTED FOR THE
PERIOD OF TIME UP TO THE FIRST SCHEDULED
REPLACEMENT POINT FOR THE PART.
ANY REPLACEMENT PART THAT IS EQUIVALENT IN
PERFORMANCE AND DURABILITY MAY BE USED IN
NON-WARRANTY MAINTENANCE OR REPAIRS, AND
SHALL NOT REDUCE THE WARRANTY OBLIGATION
OF THE COMPANY.
THE COMPANY IS LIABLE FOR DAMAGES TO OTHER
ENGINE COMPONENTS CAUSED BY THE FAILURE OF
A WARRANTED PART STILL UNDER WARRANTY.
THE WARRANTY DOES NOT APPLY TO THOSE UNITS
WHICH HAVE BEEN DAMAGED BY NEGLIGENCE OF
INSTRUCTION LISTED IN THE OWNER/OPERATOR
MANUAL FOR PROPER USE AND MAINTENANCE OF
THE UNITS ACCIDENT MISHANDLING, ALTERATION,
ABUSE, IMPROPER LUBRICATION, USE OF ANY
PARTS OR ACCESSORIES OTHER THAN THOSE
SPECIFIED BY THE COMPANY, OR OTHER CAUSES
BEYOND THE COMPANY'S CONTROL.
THIS WARRANTY DOES NOT COVER THOSE PARTS
REPLACED BY NORMAL WEAR OR HARMLESS
CHANGES IN THEIR APPEARANCE.
THERE ARE NO OTHER EXPRESS WARRANTIES.
IMPLIED WARRANTIES INCLUDING THOSE OF MER-
CHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE LIMITED TO TWO (2) YEARS OF HOME
USE [ONE (1) YEAR FOR ANY OTHER USE] FROM THE
ORIGINAL DELIVERY DATE.
LIABILITIES FOR INCIDENTAL OR CONSEQUENTIAL
DAMAGE UNDER ANY AND ALL WARRANTIES ARE
EXCLUDED.
IF YOU NEED TO OBTAIN MORE INFORMATION,
PLEASE CALL YOUR NEAREST SERVICE CENTER, OR
CHECK PLEASE ZENOAH WEB SITE
http://www.zenoah.net
Specific fuel consumption at maximum
engine power ............................................... 435g/kWh
Dimensions (L x W x H) (mm): ............ 370 x 235 x 270
Dry weight
Power unit only (kg): ............................................. 4.60
Cutting head:
Guide bar
Type: .......................... Carlton 16-10-N1-MHC UNB
Usable cutting lengths (in. (mm)): .............. 370mm
Saw chain
Type: ............................. Carlton N1C-BL-M-57E SK
Pitch (in. (mm)):........................................ 3/8 (9.53)
Gauge (in. (mm)):................................... 0.05 (1.27)
Specifications are subject to change wihout notice.