CHAIN SAW OWNER’S MANUAL
MODEL:DS4016CS
Caution: Before using our chain saw, please read this manual
carefully to understand the proper use of your unit. Keep this manual
available for reference at all times.
Owner’s Manual
△SAFETY FIRST
!
Instructions contained in warnings within this manual marked with a △
symbol concern critical points which must be taken into consideration to
prevent possible serious bodily injury and for this reason you are
requested to read all such instructions carefully and follow them without
fail.
!
NOTES ON TYPES OF WARNINGS IN THE MANUAL
△ WARNING
！
This mark indicates instructions which must be followed to prevent accidents
which could lead to serious bodily injury or death.
IMPORTANT
This mark indicates instructions which must be followed, or it will lead to
mechanical failure, breakdown, or damage.
NOTE
This mark indicates hints or directions useful in the use of the product.
Contents
1. Safety Precautions……………………………………………………… 2
2. Technical Specification……………………………………………….… 4
3. Operation - Preparation before Using…...……………………………
5
Operation - Starting…………………..…………………………………
7
Operation - Running ………………………………………..………… 9
Operation - Stopping……………………………………………………. 14
4. Maintenance…………..………………………………………………… 14
5. Storage……………..……………………………………………………. 18
6. Troubleshooting Guide…………………………………………………. 18
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Owner’s Manual
1.WARNING LABELS ON THE MACHINE
a. Read owner's manual before operating this
machine
b. Wear head, eye, and ear protection
c. Use the chain saw with two hands
d. Warning! Kickback danger
e. Warning/Attention
△ WARNING
！
Never remodel the product. We won’t warrant the machine if you use the
remodeled product or you don’t observe the proper usage written in the manual.
-2-
Owner’s Manual
SYMBOLS ON THE MACHINE
For safe operation and maintenance, symbols are carved in relief on the
machine. Per these indications, please be careful not to make a mistake.
a. The port to refill the “MIXED GASOLINE”
b. The port to refill the “CHAIN OIL”
c. Flipping the engine switch to the “I” (stop) direction
will stop the engine.
d. Pulling out the choke knob closes the choke.
e. “MIN”direction－the oil flow decreases
“MAX”direction－the oil flow increases
f. The position of the Carburetor Adjustments
-3-
Owner’s Manual
2. Technical Specifications
Name
Chain Saw
Type
Single cylinder, air cooled, two stroke
Model
DS4016CS
Displacement（cc）
40
Max. Power/Speed
1.2/8500
（kW/r/min）
Ignition
System
Pointless(CDI)
Carburetor
Diaphragm
Start Mode
Recoil Starting
Spark Plug
BPMR7A 、 RCJ6Y 、 L6RTC
Spark Plug Gap（mm）
0.6~0.7
Fuel
Mixture (40:1)
Lubricating Oil
FC two-stroke engine oil
Chain Oil
Bar & Chain Oil
Fuel Tank Capacity（oz.）
10.48
Oil Tank Capacity（oz.）
7.10
0.7
Sprocket（Teeth×Pitch）
Guide Bar Size
6T×0.375"
297X255X245
1.0
16"
300X240X250
Pitch
0.375"
Gauge
0.050"
Weight (Power unit only)
9.92
lbs.
0.050"
（kg）
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Owner’s Manual
3.Operation
BEFORE USING THE MACHINE
a. Read this owner’s manual carefully to understand how to operate this unit
properly.
b. You should never use the product when under the influence of alcohol,
when suffering from exhaustion or lack of sleep, when suffering from
drowsiness because of having taken cold medicine, or at any other time when
a possibility exists that your judgment might be impaired or that you might not
be able to operate the machine properly and in a safe manner.
c. Never use the product under circumstances like those described below:
1. When the ground is slippery or when other conditions exist which might
make it impossible to maintain a steady posture.
2. At night, at times of heavy fog, or at any other times when your field of
vision might be limited and it would be difficult to gain a clear view of the
area.
3. During rain storms, during lighting storms, at times of strong or
gale-force winds, or at any other times when weather conditions might
make it unsafe to use this product.
d. Lack of sleep, tiredness, or physical exhaustion results in lower attention
spans, and this in turn leads to accidents and injury. Limit the amount of time
of using the machine continuously to somewhere around 10 minutes per
session, and take 10~20 minutes of rest between work sessions. Also, try to
keep the total amount of work performed in a single day under 2 hours or
less.
WORKING EQUIPMENT AND CLOTHING
a. When using the product, you should wear proper clothing and protective
equipment as follows.
(1) Helmet
(2) Protection goggles or face protector
(3) Thick work gloves
(4) Non-slip-sole work boots
(5) Ear protectors
b. And you should carry with you.
1) Attached tools and files.
2) Properly reserved fuel and chain oil.
3) Things to notify your working area (Rope, warning signs)
4) Whistle (for collaboration or emergency)
5) Hatchet or saw (for collaboration or emergency)
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Owner’s Manual
WARNING CONSIDERING HANDLING OF FUEL
a. The engine of this product is designed to run on a mixed
fuel which contains highly flammable gasoline. Never store
cans of fuel or refill the fuel tank in any place where here is
a boiler, stove, wood fire, electrical sparks, welding sparks,
or any other source of heat or fire which might ignite the
fuel.
b. Smoking while operating the product or refilling its fuel tank is extremely
dangerous. Always be sure to keep lit cigarettes away from the product
always.
c. When refilling the tank always turn off the engine first and take a careful
look around to make sure that there are no sparks or open flames
anywhere nearby before refueling.
d. If any fuel spillage occurs during refueling, use a dry rag to wipe up spills
before turning the engine back on again.
e. After refueling, screw the fuel cap back tightly onto the fuel tank and then
carry the product to a spot 3 ft. or more away from where it was refueled
before turning on the engine again.
BEFORE STARTING ENGINE
a. Check work area, the cutting object, and cutting direction. If there are
any obstacles, remove them.
b. Never start until you have a clear work area, secure footing, and a planned
retreat path from the failing tree.
c. Use caution and keep bystanders and animals out of the working area.
d. Inspect the machine and look for worn, loose, or damaged parts. Never
operate a machine that is damaged, improperly adjusted, or is not
completely and securely assembled. Make sure that the saw chain stops
moving when the throttle control trigger is released.
■ WHEN STARTING THE ENGINE
a. Always hold the machine firmly with both hands when the engine is running.
Use a firm grip with thumb and fingers encircling the handles.
b. Keep all parts of your body away from the machine when the engine is
running.
c. Before starting the engine, make sure the saw chain is not touching
anything.
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Owner’s Manual
INSTALLING GUIDE BAR AND SAW CHAIN
A standard saw unit package contains the items as
illustrated
(1) power unit
(2) Bar protector
(3) Guide bar
(4) Saw chain
(5) Plug wrench
(6) Hexagon wrench
Open the box and install the guide bar and the saw
chain on the power unit as follows:
a. Loosen the nuts and remove the chain cover.
b. 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 chain
tensioner nut on the chain cover to the lower hole of
guide bar.
(1) Tensioner nut
(2) Chain cover
NOTE
Pay attention to the correct direction of the saw
chain
a. Mount the bar to the studs of the power unit, and
fit the saw chain around the guide bar, adjust the
position of chain tensioner nut on the chain.
b. Tighten the tensioner screw.
(Style 1 or Style 2）
(1) Tighten
(2) Loosen
(3) Tensioner screw
NOTE
Style 1
（2）
（3
）
（1）
Style 2
A new chain will extend its length in the beginning of use. Check and readjust
the tension frequency as a loose chain can easily derail or cause rapid wear of
itself and the guide bar.
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Owner’s Manual
Starting
■Starting engine
1. Fill fuel and chain oil tanks respectively and tighten
the caps securely.
2. Put the switch to “I” position.
3. Press the primer pump quickly until it is full of fuel
4. Push the choke knob upward. The choke will close
and the throttle lever will then be set in the starting
position
⑴ Chain oil
⑵ Fuel
⑶ Switch
⑷ throttle lever
⑸ Throttle interlock
Note
⑹ Choke knob
（2）
（1）
When restarting immediately after stopping the engine,
leave the choke knob at the open position.
△ Warning
！
Do not start the engine while holding the chainsaw.
The saw chain may touch your body. It’s very
dangerous.
5. After all the preparations, pull the starter again to start
the engine.
6. When the engine start open the choke and allow the
engine to warm up for 3 minutes.
△ Warning
！
Keep clear of the saw chain as it will start rotating
upon starting of engine.
CHECKING OIL SUPPLY
After starting the engine, run the chain at medium
speed and see if chain oil is scattered off as shown in
the figure.
(1) Chain oil
-8-
（6）
Owner’s Manual
Running
a. Keep the handles dry, clean, and free of oil or fuel mixture.
b. Never touch the muffler, spark plug, or other metal parts of the engine while
the engine is in operation or immediately after stopping the engine. Doing
so could result in serious burns or electrical shock.
c. Use extreme caution when cutting small size brush and saplings because
slender material may catch in the saw chain and be whipped toward you or
pull you off balance.
d. When cutting a limb that is under tension, be alert for spring back so that
you will not be struck when the tension in the wood fibers is released.
e. Check the tree for dead branches that could fall during the felling operation.
f. Always shut off the engine before setting it down.
△ WARNING
！
a. 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 lightning fast reverse reaction, kicking
the guide bar up and back towards the operator. Either of these reactions
may cause you to lose control of saw which could result in serious personal
injury.
b. Do not rely exclusively on the safety devices built into your saw. As a chain
saw user you should take several steps to keep cutting 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 kickback and maintain
control of the saw.
3) Make certain that the area in which you are cutting is free from
obstructions. Don not let the nose of the guide bar contact a log,
branch, or any other obstructions 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.
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Owner’s Manual
SAWING
△ WARNING
！


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 properly. You must check the chain break operation
before each usage by running the saw at full the throttle for 1-2 seconds and
pushing the front hand guard forward.
The chain should stop immediately with the
engine 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 to maintain the
kickback safety leveled the saw. Removal of the
safety devices, inadequate maintenance, or incorrect replacement of the bar or
chain may increase the risk of serious personal injury due to kickback.
FELLING A TREE
a. Decide the felling direction considering the wind, lean of the tree, location of
heavy breaches, ease of job after felling and other factors.
b. Arrange a good foothold and retreat path.
c. Make a notch cut the one-third of the wood into the tree on the felling side.
d. Make a felling cut from the from the opposite side of the notch and at a level
slightly higher than the bottom of the notch.
△ WARNING
！
When you fell a tree, the sure to warn your
neighboring workers of the danger.
(1) Notch cut
(2) Felling cut
(3) Felling direction
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Owner’s Manual
Bucking and Limbing
△ WARNING
！



Always ensure your foothold. Do not stand on the log.
Be alert to the rolling over of a cut log. Especially when working on a slope,
stand on the uphill side of the log.
Follow the instructions in “For Safe Operation” to avoid kickback of the saw.
 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 bottom.
 Cutting limb of Fallen Tree
First check to which side the limbs bent. Then make
the initial cut from the bent side and finish by sawing
from the opposite side.
 Pruning of Standing Tree
Cut up from the bottom, finish down from the top.
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Owner’s Manual
ADJUSTING CARBURETOR
The carburetor on your unit has been adjusted by the factory, but may require
fine turning due to change in operating conditions.
Before adjusting the carburetor, make sure that provided are clean air/fuel
filters and fresh, properly mixed fuel.
When adjusting, take the following steps.
a. Stop engine and screw in both H and L
needles until they stop. Never force.
Then set them back the initial number
（2）
of turns as show below.
（3）
H needle：2+-1/8
(1)
L needle：2+-1/8
b. Start engine and allow it to warm up at
half-throttle.
c. Turn L needle slowly clockwise to find
1) Idle adjusting screw
a position where idling speed is
2) H needle
maximum, then set the needle back a
3) L needle
quarter (1/4) turn counterclockwise.
d. Turn idle adjusting screw (T) counterclockwise so that saw chain does not
turn. If idling speed is to slow, turn the screw clockwise.
e. Make a test cut and adjust the H needle for best cutting power, not for
maximum speed.
CHAIN BRAKE
To release brake, pull up the front guard toward
the front handle till “click” sound is heard.
(1) Break
(2) Released
(3) Operated
If the engine brakes in high speed, the clutch will be hot, and it can cause
damage to machine.
When it brakes during operation, release the throttle lever immediately to allow
the engine to idle.
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Owner’s Manual
FUEL AND CHAIN OIL
△ 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 refueling the unit.
Select outdoor bare ground for fueling and move at least 3m away
from the fueling point before starting the engine.
 Please use an anti-oxidant added quality oil expressly labeled for
air-cooled 2-cycle engine use. (JASO FCGRAD OIL or ISO EGCGRADE)
 Do not use BIA or TCW (2-stroke water-cooling type) mixed oil.
 Exhaust emission are controlled by the fundamental engine
parameters and components (eq., carburetion, ignition timing and
port timing) without addition of any major hardware or the
introduction 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 89 RON
(USA/Canada:87AL)
 If you use a gasoline of a lower octane value than prescribed, there is a
danger that the engine temperature 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 gasoline or oils may damage sealing rings, fuel lines or fuel
tank of the engine.
HOW TO MIX FUEL
Pay attention to agitation
IMPORTANT
a.
b.
c.
d.
- 13 -
Measure out the quantities of gasoline and oil to be mixed.
Put some of the gasoline into a clean, approved fuel container.
Pour in all the oil and agitate well.
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 agitation 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 abnormally lean mixture.
Owner’s Manual
FUELING THE UNIT
a. Untwist and remove the fuel cap. Rest the cap on a dustless place.
b. Put fuel into the fuel tank to 80％ of the full capacity.
c. Fasten the fuel cap securely and wipe up any fuel spillage around the
unit.
△ WARNING
！
a. Move at least 10feet (3meters) away from the fueling point before
starting the engine.
b. Stop the engine before refueling the sufficiently agitate the mixed
gasoline in the container.
FOR YOUR ENGINE LIFE, AVOID:
a. FUEL WITH NO OIL (RAW GASOLINE) - It will cause severe damage to
the internal engine parts very quickly.
b. GASOHOL – It can cause deterioration of rubber and/or plastic parts and
disruption of engine lubrication.
c. OIL FOR 4-CYCLE ENGINE USE – It can cause spark plug fouling,
exhaust port blocking, or piston ring sticking.
d. In the case of storing the product for a long period, clean the fuel tank
after rendering it empty the carburetor of the composite fuel.
CHAIN OIL
Always use a Chainsaw rated Bar & Chain oil to provide proper lubrication of
the bar, chain, and oil pump system.
Stopping engine
To stop the engine in an emergency, move the stop switch to the “O” position.
Under normal conditions, use the following procedure:
1. Release the throttle lever to allow the engine
to idle for 3 minutes.
2. Put the switch to the “O” position.
(1)
(1) Switch
- 14 -
Owner’s Manual
4. MAINTENANCE
△ WARNING
！
Before cleaning, inspecting or repairing your unit, make sure that engine
has stopped and is cool. Disconnect the spark plug to prevent accidental
starting.
MAINTENANCE AFTER EACH USE
a. Air Filter
To clean dirt in the meshes, split the cleaner into
halves and brush in gasoline. When using
compressed air, blow from the inside.
b. Oiling port
Dismount the guide bar and check the oiling port for
clogging.
(1) Oiling port
c. 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.
(1) Oiling port
(2) Grease
port
(3) Sprocket
- 15 -
Owner’s Manual
Service Points
a. Cylinder fins
Dust clogging between the cylinder fins will cause over
heating of the engine. Periodically check and clean the
cylinder fins after removing the air cleaner and the
cylinder cover.
Cylinder fins
Note
Be sure to block the air intake hole.
b. Fuel filter
a. Using a wire hook, take out the filter from the
filler port.
b. Disassemble the filter and wash with gasoline.
(
(1) Fuel filter
Note
After removing the filter, use a pinch to hold the end of the suction pipe, take
care not to allow filters or dust inside the suction pipe.
c. Oil tank
With a wire hook, take out the oil filter through the filler port and clean in
gasoline. When putting the filter back into the tank, make sure that it comes to
the front right corner. Also, clean off dirt in the tank.
d. Spark plug
Clean the electrodes with a wire brush and reset
the gap to 0.6~0.7 mm as necessary.
e. Sprocket
Check for cracks and for excessive wear interfering with the chain drive. If the
wearing is found obviously. Replace it with new one. Never fit a new chain on
worn sprocket, or a worn chain on a new sprocket.
- 16 -
Owner’s Manual
MAINTENCE OF SAW CHAIN AND GUIDE BAR
△ WARNING
！
It is very important for smooth and safe operation to
keep the cutters always sharp.
a. Your cutters need to be sharpened when:
 Sawdust becomes powdery/fine.
 You need extra force to saw in.
 The cut line does not go straight.
 Vibration increases.
 Fuel consumption increases.
b. Cutter setting standards:
 Make sure the saw chain is held securely.
 Make sure the engine is stopped.
 Use a round file of proper size for your chain.
Place your file on the cutter and push straight forward.
Keep the file position as illustrated. After every cutter has been set, check the
depth gauge and file it to the proper level as illustrated.
△ WARING
！
Be sure to round off the front edge to reduce the
chance of kickback or tie-strap breakage.
(1) Appropriate gauge
checker
(2) Make the shoulder round
(3) Depth gauge standard
Make sure every cutter has the same length and
edge angles as illustrated.
(4) Cutter length
(5) Filing angle
(6) Side plate angle
(7) Top plate cutting angle
GUIDE BAR
Reverse the bar occasionally to prevent partial wear.
- 17 -
Owner’s Manual
5. Storage
If the chain saw isn’t going to be used for a long time, maintain as follows:
1) Remove the fuel, the chain oil in the tank, and in the carburetor.
2) Take off the spark plug, add a small amount of oil down the spark plug hole
into the cylinder, and pull the starter 2~3 times to move the piston to the top
dead center, then replace the spark plug.
3) Use a soft cloth with engine oil to clean the surface of the engine, put the
engine to the dry and ventilated place for the next use.
6. Troubleshooting Guide
1) Starting Failure
Description
Cause
Countermeasure
No spark at the plug
Spark plug
Magneto
1) Wet spark plug electrodes
2) Carbon deposited on the
electrodes
3) Insulation failure by insulator
damage
Dry
Clean
4) Improper spark gap
Replace
Adjust to
0.6-0.7mm
5) Burn out of electrodes
1) Damaged cable
2) Ignition coil inside failure
3) Disconnected cable
Replace
Replace
Replace
Repair
There is spark at the plug
Compression
& fueling is
normal
Fueling
1) Overflow of fuel
Reduce
2) Fuel is bad /dirty or mixed with
water
Change
normal but
ring
Replace
2) Spark plug loose
Tighten
1) No fuel in the tank
2) Fuel tube clogged
3)The valve of the fuel tank cap
clogged
Fill the tank
Clean
1) Worn out cylinder and piston
poor
compression
No fuel supply
- 18 -
Clean
Owner’s Manual
2) Lack of Power
Description
Cause
1) Clogged element
2) Air penetration from
carburetor joint
3) Faulty fuel
4) Engine overheating
Compression is
normal and no
misfire
Countermeasure
Clean
Tighten
Replace
Cool down, avoid long
time operation in high
speed or overloading
5) Muffler choked with
carbon
Clean
6) Carbon deposited on
the exhaust port of
cylinder
1) Fuel too lean
2) Carbon deposited in
the cylinder
Overheating
Abnormal knocking
sound
- 19 -
3) Poor lubrication
4) Clogging of cylinder
fin with dust
1) Carbon deposited in
the combustion
chamber
2) Running parts worn
out
Clean
Adjust carburetor
Clean
Use 2-stroke engine oil,
adjust fuel ratio
Clean
Clean
Check and replace
Owner’s Manual
3) Stop during operation
Description
Cause
Countermeasure
File the cylinder and piston,
Stop
abruptly
Stop
gradually
1) Piston burn out
replace the piston ring
2) Short circuit of spark
plug electrodes
Clean
3) Magneto inside failure
Check
1) Lack of fuel
Refuel
2) Clogged carburetor
Check and clean
Replace
3) Fuel with water
4) Oil in the oil pump does not come out or the oil flow is very little
Description
Cause
Countermeasure
1) Oil is not adjusted properly Adjust the lever to the “＋”
Oil flow is
2) Oil outlet tube clogged
Remove the guide bar, clean.
very little
3) Oil tube broken
Check and replace oil tube
4) Oil filter strainer clogged
Clean with gasoline
1) Lack of chain oil
Refill
2) Oil outlet tube clogged
Remove the guide bar, clean.
3) Aging of the oil tube
Replace oil tube
4) Oil pump clogged
Clean or replace oil pump
5) Oil filter strainer clogged
Replace the oil filter
Oil does not
come out
- 20 -
DuroStar Power Equipment
5798 Ontario Mills Pkwy
Ontario CA 91764
800-629-3325 M – F 7:00a – 5:00p PT
support@maxtool.com