Echo CS-310 User manual

X7503270002 X750011672
04/10
WARNING
Read rules for safe operation and instructions carefully. ECHO provides an Instruc-
tion Manual and a Safety Manual. Both must be read and understood for proper and
safe operation.
Chain Saw
Instruction Manual
MODEL : CS-310

2
CS-310
RULES FOR SAFE OPERATION
A. Kickback Safety Precautions for Chain Saw Users
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 rm 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 rm grip with thumbs and ngers
encircling the chain saw handles.
A rm grip will help you reduce
kickback and maintain control of the
saw.
Don’t let go.
3. Make sure 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 manufacturer’s sharpening and
maintenance instructions for the saw
chain.
7.Only use replacement bars and chains
specied by the manufacturer or the
equivalent.
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
lightning fast reverse REACTION, Kick-
ing the guide bar up and back towards the
operator.
Pinching the saw chain along the top of
the guide bar may push the guide bar rap-
idly back towards the operator.
Either of these reactions may cause you to
lose control of the saw which could result
in serious personal injury.
The Kick Guard®device is not installed
on the guide bar when you purchase your
ECHO chain saw.
The Kick Guard®can be used in a majority
of cutting operations, and is especially rec-
ommended for beginners, homeowners, or
chain saw novices.
Most cutting operations can be accom-
plished with the Kick Guard®in place.
Do not rely exclusively upon the safety
devices built into your saw.
As a chain saw user, you should
take several steps to keep your cutting
jobs free from accident or injury.
Copyright© 2010 By Echo, Incorporated
All Rights Reserved.

3CS-310
1. Do not operate a chain saw with
one hand! Serious injury to the
operator, helpers, bystanders, or any
combination of these persons may
result from one-handed operation.
A chain saw is intended for two-handed
use.
2. Do not operate a chain saw when you
are fatigued.
3. Use safety footwear, snug-tting
clothing and protective gloves.
Wear eye, hearing, and head
protection devices.
4. Use caution when handling fuel.
Move the chain saw at least 3 m
(10 feet) from the fueling point before
starting the engine.
5. Do not allow other persons to be near
the chain saw when starting or cutting
with the chain saw.
Keep bystanders and animals out of
the work area.
6.Do not start cutting until you have a
clear work area, secure footing, and
a planned retreat path from the falling
tree.
7. Keep all parts of your body away from
the saw chain when the engine is
running.
8.Before you start the engine, make sure
that the saw chain is not contacting
anything.
9. Carry the chain saw with the engine
stopped, the guide bar and saw chain
to the rear, and the mufer away from
your body.
10. Do not operate a chain saw that is
damaged, improperly adjusted, or not
completely and securely assembled.
Be sure that the saw chain stops
moving when the throttle control trigger
is released.
11.Shut off the engine before setting the
chain saw down.
12. Use extreme caution when cutting
small size brush and saplings because
slender material may catch the saw
chain and be whipped toward you or
pull you off balance.
13.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 bers is released.
14.Keep the handles dry, clean, and free
of oil or fuel mixture.
15. Operate the chain saw only in well
ventilated areas.
16. Do not operate a chain saw in a tree
unless you have been specically
trained to do so.
17. All chain saw service, other than
items listed in the Instruction manual
maintenance instructions, should
be performed by competent service
personnel.
(For example, if improper tools are
used to remove the ywheel or if
an improper tool is used to hold the
ywheel in order to remove the clutch,
structural damage to the ywheel could
occur and could subsequently cause
the ywheel to burst.)
18. When transporting your chain saw, use
the appropriate guide bar scabbard.
19. Spark arrestor mufers approved to
SAE Standard J335 are standard
on ECHO chain saws to reduce the
possibility of forest res.
Do not operate the chain saw with a
loose or defective mufer.
Do not remove the spark arrestor
screen.
B. Other Safety Precautions

4
CS-310
WARNING
Using improper replacement components or removing safety devices may result in serious or fatal injury.
WARNING
• During operation, the mufer or catalytic mufer and surrounding cover become hot.
• Never suspend the saw on a lanyard with the engine running.
• Always use the saw from the right-hand side of your body – NEVER from the left side.
• Always wear proper safety clothing to protect your lower body from sharp saw chain and hot mufer.
• Always keep exhaust area clear of ammable debris during transportation or when storing, otherwise
serious property damage or personal injury may result.
WARNING
Moving parts can amputate ngers or cause severe injuries. Keep hands, clothing and loose objects away from
all openings.
• ALWAYS stop engine, disconnect spark plug, and make sure all moving parts have come to a complete stop
before removing obstructions, clearing debris, or servicing unit.
• DO NOT start or operate unit unless all guards and protective covers are properly assembled to unit.
• NEVER reach into any opening while the engine is running. Moving parts may not be visible through openings.
WARNING
Check fuel system for leaks due to fuel tank damage, especially if the unit is dropped. If damage or leaks are
found, do not use unit, otherwise serious personal injury or property damage may occur. Have unit repaired by an
authorized servicing dealer before using.

5CS-310
WARNING
Thesafetyalertsymbolaccompaniedbytheword
“WARNING”callsattentiontoanactorcondition
whichCANleadtoseriouspersonalinjuryordeath
if not avoided.
CIRCLE AND SLASH SYMBOL
This symbol means the specic action
shown is prohibited. Ignoring these
prohibitions can result in serious or
fatal injury.
CAUTION
Thesafetyalertsymbolaccompaniedbytheword
“CAUTION”callsattentionto anactorcondition
which may lead to minor or moderate personal
injury if not avoided.
NOTE
This enclosed message provides tips for use,
care and maintenance of the unit.
IMPORTANT
The enclosed message provides information
necessary for the protection of the unit.
DANGER
Thesafetyalertsymbolaccompaniedbytheword
“DANGER” calls attention to an act or condition
whichWILLleadtoseriouspersonalinjuryordeath
if not avoided.
SYMBOLS AND SIGNS
CONTENTS
RULES FOR SAFE OPERATION ............................................................................ 2
SYMBOLS AND SIGNS ........................................................................................... 5
EMISSION DATA ..................................................................................................... 7
PACKING LIST......................................................................................................... 7
NOMENCLATURE OF PARTS ................................................................................ 8
OPERATOR SAFETY .............................................................................................. 10
CORRECT USE OF CHAIN BRAKE........................................................................ 11
PREPARATION FOR USE....................................................................................... 12
FUEL AND LUBRICANT .......................................................................................... 14
OPERATION ............................................................................................................ 16
CUTTING INSTRUCTION........................................................................................ 19
CHAIN AND GUIDE BAR COMBINATION............................................................... 24
MAINTENANCE AND CARE.................................................................................... 25
Carburetor Adjustment............................................................................................. 26
- High Altitude Operation ........................................................................................ 26
SETTING THE SAW CHAIN .................................................................................... 30
TROUBLESHOOTING ............................................................................................. 32
STORAGE AFTER USE........................................................................................... 33
TECHNICAL DATA................................................................................................... 33
WARRANTY STATEMENTS.................................................................................... 34
SERVICING INFORMATION.................................................................................... 40
This chain saw is designed for cutting wood or wood products. Do not cut solid metal, sheet
metal, plastic or any non-wood materials.
Specications, descriptions and illustrative material in this literature are as accurate as known
at the time of publication, but are subject to change without notice.
Illustrations may include optional equipment and accessories, and may not include all standard
equipment.

6
CS-310
SYMBOL FORM
TO AVOID KICKBACK
1.Holdthechainsawrmlywithboth
hands.
2.Don’tletthenoseoftheguidebar
contactanyobstruction.
3.Tipcontactmaysuddenlymovethe
guidebarupwardandbackward,
whichmaycauseseriousinjury.
Part Number 89019130131
Carburetor adjustment
- Idle speed
Carburetor adjustment
- High speed mixture
Carefully read the Instruction
manual
Wear eyes, ears and head
protection
Carburetor adjustment
- Low speed mixture
Oil and gasoline mixture
Symbol form/shape Symbol description/application Symbol form/shape Symbol description/application
Chain brake operation
Chain oil ll
DECALS
Locate these safety decals on your unit. The
complete unit illustration found in the “NOMEN-
CLATURE OF PARTS” section will help you locate
them. Make sure the decals are legible and that
you understand and follow the instructions on
them. If a decal cannot be read, a new one can be
ordered from your ECHO dealer.
Emergency stop
Choke control “Cold Start”
position (choke closed)
STOP
Part Number X503-009360
WARNING!!Readandfollowallsafety
precautionintheinstructionmanual.
Failuretofollowinstructionscould
resultinseriouspersonalinjury.
CS-310
Part Number X524-002190
REPLACEMENT BAR AND CHAIN
GUIDE BAR* CHAIN*
PART NO. TYPE LINKS
12” 12A0CD3745 OREGON 91VG / 91P 45
14” 14A0CD3752 OREGON 91VG / 91P 52
16” 16A0CD3757 OREGON 91VG / 91P 57
Note: Theremaybeotherreplacement
componentsforachievingkickback
protection.Fordetails,pleaserefer
tothechainandbarcombina-
tionsheetshownintheinstruction
manual.

7CS-310
PACKING LIST
The ECHO product you purchased has been fac-
tory pre-assembled for your convenience. Due to
packaging restrictions, guide bar and saw chain
installation and other assembly may be necessary.
After opening the carton, check for damage. Im-
mediately notify your retailer or ECHO dealer of
damaged or missing parts. Use the packing list to
check for missing parts.
Warrantyregistrationcard
13 x 19 mm T-wrench
ECHO Power Blend X™
2-stroke oil sample
Instruction manual Safety manual
ECHO chain saw
Saw chain
Guide bar
Kick Guard®
Em i s s i o n Da t a
An Emission Control Label is located on the engine. (This
is an EXAMPLE ONLY, information on label varies by
engine FAMILY).
PRODUCT EMISSION DURABILITY (EMISSION COMPLIANCE PERIOD)
The 300 hour emission compliance period is the time span selected by the manufacturer certifying the engine emis-
sions output meets applicable emissions regulations, provided that approved maintenance procedures are followed
as listed in the Maintenance Section of this manual.
E m i s s i o n c o n t r o l (E x h a u s t &E v a p o r a t i v E )
EPA 2010 and Later and/or C.A.R.B. TIER III
The emission control system for the engine is EM/TWC
(Engine Modication and 3-way Catalyst) and for the fuel
tank the Control System is EVAP (Evaporative Emissions)
or N (for nylon tank). Evaporative emission may be appli-
cable to California models only.

8
CS-310
NOMENCLATURE OF PARTS
* Ifadecalcannotberead,anewonecanbeordered
fromyourECHOdealer.
18
13
14
15
17
16
5
4
8
7
10
11
12
3
2
1
X524-002190
89019130131
X503-009360
9
20
6
21
Part Number X503-009360
WARNING!!Readandfollowallsafety
precautionintheinstructionmanual.
Failuretofollowinstructionscould
resultinseriouspersonalinjury.
CS-310
TO AVOID KICKBACK
1.Holdthechainsawrmlywithboth
hands.
2.Don’tletthenoseoftheguidebar
contactanyobstruction.
3.Tipcontactmaysuddenlymovethe
guidebarupwardandbackward,
whichmaycauseseriousinjury.
Part Number 89019130131
19
Part Number X524-002190
REPLACEMENT BAR AND CHAIN
GUIDE BAR* CHAIN*
PART NO. TYPE LINKS
12” 12A0CD3745 OREGON 91VG / 91P 45
14” 14A0CD3752 OREGON 91VG / 91P 52
16” 16A0CD3757 OREGON 91VG / 91P 57
Note: Theremaybeotherreplacement
componentsforachievingkickback
protection.Fordetails,pleaserefer
tothechainandbarcombina-
tionsheetshownintheinstruction
manual.

9CS-310
1. Instruction manual - Included with unit.
Readbeforeoperationandkeepforfuture
referencetolearnproper,safeoperatingtech-
niques.
2. Safety manual-Describeoperatingandsafety
instructionsforthischainsaw.
3. Front hand guard-Guardbetweenthefronthan-
dleandthesawchainforprotectingthehand
frominjuriesandaidingincontrolofthechain
saw if the hand slips off the handle.
Thisguardisusedtolockthechainbrakewhich
istostopthesawchainrotation.
4. Choke control knob-Deviceforenrichingthe
fuel/airmixtureinthecarburetortoaidcold
starting.
5. Purge pump-Whenstartingengine,pushpurge
pump3or4times.
6. Rear hand guard-Extensiononthelowerpartof
therearhandleforprotectingthehandfrom
thechainifitbreaksordegrooves.
7. Clutch cover-Protectivecovertotheguidebar,
sawchain,clutchandsprocketwhenthechain
saw is in use.
8. Chain tension adjuster-Devicetoadjustchain
tension.
9. Chain catcher-Aprojectiondesignedtoreduce
theriskoftheoperator’srighthandfrombeing
hitbyachainwhichhasbrokenorderailed
fromtheguidebarduringcutting.
10. Guide bar-Thepartthatsupportsandguidesthe
saw chain.
11. Saw chain-Chain,servingasacuttingtool.
12. Bar tip guard-Anti-kickbackdeviceattachedon
thebarnose.
NOMENCLATURE OF PARTS
13. Oil tank cap-Forclosingtheoiltank.
14. Front handle (for the left hand)-Supporthandle
locatedatthefrontoftheenginehousing.
15. Starter handle-Pullhandleslowlyuntilstarter
engagesthenquicklyandrmly.Whenen-
ginestarts,returnhandleslowly. 
   DONOTlethandlesnapbackordamageto
unitwilloccur.
16. Fuel tank cap-Forclosingthefueltank.
17. Ignition switch-Deviceforconnectinganddis-
connectingtheignitionsystemandthusallow-
ingtheenginetobestartedorstopped.
18. Throttle trigger-Deviceactivatedbytheopera-
tor’snger,forcontrollingtheenginespeed.
19. Rearhandle(fortherighthand)-Supporthandle
locatedtowardstherearoftheenginehousing.
20.Throttletrigger lockout-Asafetyleverwhichmust
bedepressedbeforethethrottletriggercan
beactivatedinordertopreventtheaccidental
operationofthethrottletrigger.
21. Cylinder cover-Thecoolingairowgrill.Itcovers
thecylinder,airltter,sparkplugandsilencer.

10
CS-310
VIBRATION AND COLD
• It is believed that a condition called Raynaud’s
Phenomenon, which affects the ngers of
certain individuals, may be brought about by
exposure to vibration and cold.
Exposure to vibration and cold may cause
tingling and burning followed by loss of color
and numbness in the ngers.
The following precautions are strongly recom-
mended because the minimum exposure which
might trigger the ailment is unknown.
• Keep your body warm, especially the head and
neck, feet and ankles and hands and wrists.
• Maintain good blood circulation by performing
vigorous arm exercises during frequent work
breaks and also by not smoking.
• Limit the number of hours of operation.
Try to ll each day with jobs where operating the
chain saw, or other hand-held power equipment
is not required.
• If you experience discomfort redness and swell-
ing of the ngers, followed by whitening and loss
of feeling, consult your physician before further
exposing yourself to cold and vibration.
REPETITIVE STRESS INJURY
• It is believed that over-using the muscles and
tendons of the nger, hands, arms and shoul-
ders may cause soreness, swelling, numbness,
weakness and extreme pain to the areas just
mentioned.
Certain repetitive hand activities may put you
at a high risk for developing a repetitive stress
injury (RSI).
• An extreme RSI condition is Carpal Tunnel
Syndrome (CTS) which could occur when your
wrist swells and squeezes a vital nerve that runs
through the area. Some believe that prolonged
exposure to vibration may contribute to CTS.
CTS can cause severe pain for months or even
years.
To reduce the risk of RSI/CTS, do the following:
• Avoid using your wrist in a bent, extended or
twisted position.
• Take periodic breaks to minimize repetition and
rest your hands.
• Reduce the speed and force in which you do the
repetitive movement.
• Do exercises to strengthen hand and arm mus-
cles.
• See a doctor if you feel tingling, numbness or
pain in your ngers, hands, wrists or arms.
The sooner RSI/CTS is diagnosed, the more
likely permanent nerve and muscle damage can
be prevented.
EYE AND HEARING PROTECTION
• Wear eye protection goggles that meet ANSI
Z 87.1 requirements.
Goggles meeting the requirements have
the mark “Z 87” stamped on them.
• Wear hearing protection.
If this guideline is not followed, hearing loss can
occur.
ECHO recommends wearing hearing protection
at all times.
WEAR PROPER CLOTHING
• Snug tting durable clothing should be worn.
Pants should have long legs, DO NOT WEAR
SHORTS.
Do not wear loose tting clothing, scarves,
neckties, jewelry or any item that may become
tangled in surrounding growth or the chain saw
itself.
• Wear shoes with non-skid soles.
DO NOT wear open toed shoes or operate unit
barefooted.
• Wear no-slip, heavy duty work gloves to improve
your grip on the chain saw handles.
The gloves also help reduce the transmission of
machine vibration to your hands.
• Keep long hair away from engine and air intake.
Retain hair with cap or net.
HOT HUMID WEATHER
• Heavy protective clothing can increase operator
fatigue which may lead to heat stroke.
Schedule heavy work for early morning,
or late afternoon hours when temperatures are
cooler.
AVOID HOT SURFACES
• During operation, the mufer or catalytic mufer
and surrounding cover become hot.
• Never suspend the saw on a lanyard with the
engine running.
• Always use the saw from the right-hand side of
your body - NEVER from the left side.
• Always wear proper safety clothing to protect
your lower body from sharp saw chain and hot
mufer.
• Always keep exhaust area clear of ammable
debris during transportation or when storing,
otherwise serious property damage or personal
injury may result.
OPERATOR SAFETY

11 CS-310
SPARK ARRESTOR MUFFLER
• The spark arrestor mufer controls the exhaust
noise and prevents hot, glowing particles of
carbon from leaving the mufer.
Make sure the spark arrestor screen is in good
repair and properly seated in the mufer.
• Certain internal combustion engines operated on
forest, brush, and/or grass-covered areas in the
states of Washington, Oregon, Idaho, California,
Minnesota, New Jersey and Maine, are required
to be equipped with a spark arrestor.
CORRECT USE OF CHAIN BRAKE
Liner kickback
Rotational kickback
Chain moving downward at impact
Rotational kickback
Reduced
radius
Pinch
Kickback
This requirement also applies to all U.S. Forest
Service lands.
In some of these areas, the spark arrestor system
must be certied per USDA Forest Service Regula-
tion SAE J335.
Check with your local or state authorities for spe-
cic regulations in your area.
Failure to follow these requirements is a violation
of the law.
DANGER
Kickbacksafetyprecautionforchainsawusers:
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.
The installation of a chain brake may be mandatory
by law or as stipulated by insurance regulations in
your area of operation.
You should inquire through local government of-
ces, your employer or your local dealer to ensure
that your chain saw conforms to the required safety
standard.
ECHO chain brakes have been designed and
tested to comply with international safety standards
as follows.
USA : ANSI Standard B175.1 - 2000
Safety Requirement for chain saws
Canada : CSA Standard Z 62.1 CHAIN SAWS
WARNING
ANSI Standard B175. 1 - 2000 stipulates that
the brake shall stop the chain 0.12 seconds
at an engine speed of 13500 r/min.
It is the responsibility of the owner/operator
to ensure that the brake is serviced, adjusted
and tested strictly in accordance with the
instructions as detailed herein in order
to ensure that the brake performance is
maintaind in compliance with the Standard
B175. 1 - 2000.

12
CS-310
PREPARATION FOR USE
Bolt (A)
Dimple (D)
Recess (E)
Front hole (C)
Rear hole (B)
Nut (F)
Guide bar
Kick Guard®
WARNING
Saw chain is sharp! Always wear gloves when
handling assembly, otherwise serious personal
injury may result.
NOTE
The machine may be delivered with guide bar,
tip guard, and saw chain separated. Install
guide bar, tip guard, and saw chain as follows.
KICKGUARD®TOBARINSTRUCTIONS
Tools Needed: Two 11 mm (7/16 in.) Wrenches.
For saws with Kick Guard®P/N 2893201 and
Symmetrical Low-Kick type (Double Guard)
guide bars.
1. Install bolt (A) in rear hole (B) of Kick Guard®
and through front hole (C) in guide bar.
2. IMPORTANT: Dimple (D) in Kick Guard®must
engage recess (E) in guide bar.
3. Tighten nut (F) and bolt (A) using 11 mm (7/16
in.) wrenches until snug. Make certain Kick
Guard® is ush against guide bar.
4. Tighten nut (F) 1/8 additional turn.
5. Check to make certain Kick Guard®is tight on
guide bar.
GUIDE BAR AND SAW CHAIN IN-
STALLATION/REMOVAL
1. Release the cylinder cover latches, and remove
the cylinder cover.
2. Remove spark plug lead.
3. Remove two clutch cover nuts and remove
clutch cover.
4. Remove bar and saw chain if necessary. See
“Maintenance and Care” section for guide bar/
saw chain maintenance procedures.
Clutch cover
Two nuts

13 CS-310
4. Mount guide bar on studs and slide toward
clutch to make saw chain installation easier. In-
stall chain with cutters on top of guide bar facing
forward.
5. Install the clutch cover over the guide bar studs.
Ensure chain tension adjuster pin ts into the
guide bar adjuster hole. Tighten clutch cover
nuts nger tight.
ADJUSTING CHAIN TENSION
IMPORTANT
Always loosen clutch cover nuts before turning
the chain tension adjuster, otherwise the clutch
cover and tensioner will be damaged.
1. Release the cylinder cover latches, and remove
the cylinder cover. Remove spark plug lead.
2. Loosen two clutch cover nuts, if necessary.
3. Hold the bar nose up, and turn the adjuster
screw clockwise until chain ts snugly against
underside of the bar.
4. Tighten both nuts with the bar nose held up.
5. Pull the chain around the bar by hand. Loosen
the adjustment if you feel tight spots.
6. When chain is properly tensioned, tighten clutch
cover nuts securely - 20 to 23 N·m (175 to 200
in. lb.).
7. Keep chain properly tensioned at all times.
Adjusting screw
Proper tension Improper tension
Direction to tension the chain
Guide bar
adjuster
hole
Clutch cover
Nuts
Adjuster pin
Clutch Guide bar studs
NOTE
All chains require frequent adjustments.

14
CS-310
Handling Fuel
WARNING
Fuel is VERY ammable. Use extreme care when mixing, storing or handling or serious personal injury may result.
• Use an approved fuel container.
• DO NOT smoke near fuel.
• DO NOT allow ames or sparks near fuel.
• Fuel tanks/cans may be under pressure. Always loosen fuel caps slowly allowing pressure to equalize.
• NEVER refuel a unit when the engine is HOT or RUNNING!
• DO NOT ll fuel tanks indoors. ALWAYS ll fuel tanks outdoors over bare ground.
• DO NOT overll fuel tank. Wipe up spills immediately.
• Securely tighten fuel tank cap and close fuel container after refueling.
• Inspect for fuel leakage. If fuel leakage is found, do not start or operate unit until leakage is repaired.
• Move at least 3m (10 ft.) from refueling location before starting the engine.
Fu E l a n D lu b r i c a n t
NOTICE: Use of unmixed, improperly mixed, or fuel older than 90 days, (stale fuel), may cause hard starting, poor perfor-
mance, or severe engine damage and void the product warranty. Read and follow instructions in the Storage section of this
manual.
F u E l s t a t E m E n t
WARNING
Alternative fuels, such as E-15 (15% ethanol), E-85 (85% ethanol) or any fuels not meeting ECHO requirements are NOT
approved for use in ECHO 2-stroke gasoline engines. Use of alternative fuels may cause performance problems, loss of
power, overheating, fuel vapor lock, and unintended machine operation, including, but not limited to, improper clutch
engagement. Alternative fuels may also cause premature deterioration of fuel lines, gaskets, carburetors and other engine
components.
Gasoline - Use 89 Octane [R+M/2] (mid grade or higher) gasoline known to be good quality. Gasoline may contain up to 10%
Ethanol (grain alcohol) or 15% MTBE (methyl tertiary-butyl ether). Gasoline containing methanol (wood alcohol) is NOT ap-
proved.
Two Stroke Oil - A two-stroke engine oil meeting ISO-L-EGD (ISO/CD 13738) and J.A.S.O. FC/FD Standards must be used.
Echo brand premium Power Blend XTM Universal 2-Stroke Oil meets these standards. Engine problems due to inadequate lubrica-
tion caused by failure to use an ISO-L-EGD (ISO/CD 13738) and J.A.S.O. FC/FD certied oil, such as Echo premium Power
Blend XTM, will void the two-stroke engine warranty.
IMPORTANT
Echo premium Power Blend XTM Universal 2-Stroke Oil may be mixed at 50:1 ratio for application in all Echo engines sold
in the past regardless of ratio specied in those manuals.

15 CS-310
Mixing Instructions
1. Fill an approved fuel container with half of the required
amount of gasoline.
2. Add the proper amount of 2-stroke oil to gasoline.
3. Close container and shake to mix oil with gasoline.
4. Add remaining gasoline, close fuel container, and remix.
IMPORTANT
Spilled fuel is a leading cause of hydrocarbon emissions.
Some states may require the use of automatic fuel shut-off
containers to reduce fuel spillage.
After use
• DO NOT store a unit with fuel in its tank. Leaks can occur.
Return unused fuel to an approved fuel storage container.
Storage - Fuel storage laws vary by locality. Contact your local
government for the laws affecting your area. As a precaution, store
fuel in an approved, airtight container. Store in a well-ventilated,
unoccupied building, away from sparks and ames.
Fuel Mix Chart
50:1
IMPORTANT
Stored fuel ages. Do not mix more fuel than you
expect to use in thirty (30) days, ninety (90) days
when a fuel stabilizer is added.
IMPORTANT
Stored two-stroke fuel may separate. ALWAYS
shake fuel container thoroughly before each use.
Oil tank cap
Fuel tank cap
Cap indication
Fuel/oil tanks are indicated by the following
illustrations.
CHAIN LUBRICANT
Proper lubrication of the chain while in operation
reduces friction between the chain and the guide
bar to a minimum and assures a longer service life.
• Use bar and chain oil of high quality for this
purpose.
• Do not use used or reclaimed oil to avoid vari-
ous oiler problems.
• Use ECHO bar and chain oil.
• When ECHO bar and chain oil is not available:
Use motor oil, etc.
• Use bar and chain oil of the following grades:
SAE No. 30....... in summer
SAE No. 10....... in winter or when cutting resin-
ous trees.
• When refueling, also rell chain oil.

16
CS-310
WARNING
•Afterchokecontrolknobispulledandthenknob
isreturnedtooriginalposition,throttleremains
slightly open (latch condition).
•Thechainwillattempttorotatewhen  
engine is started with throttle latch
engaged.
•Donotstartenginebeforechainbrakeis  
activated.
CAUTION
•Afterstartingtheengine,squeezethrottletrigger
slightlytoreleasethrottlelatchotherwisebrake
damage may occur.
•Neverusethrottlelatchforcutting.
•Usethechainbrakeonlyinstartingorin
emergencies.
OPERATION
Start / Run
Ignition
switch
Chain brake
Starter handle
Choke
Choke control knob
Purge pump
WARNING
Moving parts can amputate ngers or cause severe injuries. Keep hands, clothing and loose objects away from
all openings. Always stop engine, disconnect spark plug, and make sure all moving parts have come to a com-
plete stop before removing obstructions, clearing debris, or servicing unit.
WARNING
Engine exhaust IS HOT, and contains Carbon Monoxide (CO), a poison gas. Breathing CO can cause uncon-
sciousness, serious injury, or death. Exhaust can cause serious burns. ALWAYS position unit so that exhaust is
directed away from your face and body.
WARNING
Operation of this equipment may create sparks that can start res around dry vegetation. This unit is equipped
with a spark arrestor and a spark arrestor may be required. The operator should contact local re agencies for
laws or regulations relating to re prevention requirements.

17 CS-310
WHEN THE ENGINE IS WARM
CAUTION
Make sure the bar and chain are free from any obstruction
when starting the chain saw.
• Move chain brake lever fully forward to lock chain brake
before starting.
• Conrm there is fuel and chain oil in the tanks.
• Move ignition switch to “RUN” position.
• Securely hold the chain saw as shown and pull
starter handle.
• Choke may be used if necessary, but after rst ring sound,
pull throttle trigger to release choke.
WHEN THE ENGINE IS COLD
CAUTION
Makesurethebarandchainarefreefromanyobstruction
when starting the chain saw.
• Move chain brake lever fully forward to lock chain brake
before starting.
• Fill the fuel tank with fuel mixture. Do not over ll.
• Fill the chain oil tank with lubricant.
Do not over ll.
• Move ignition switch to “RUN” position.
• Push purge pump 3 to 4 times or until fuel is visible in
purge pump.
• Pull choke control knob all the way out. (Choke position)
NOTE
Do not pull starter rope out to the maximum possible
position.
Do not allow recoil handle to snap back against the cas-
ing.
• Securely hold the chain saw as shown and pull starter
handle several times until rst ring sound.
• Push choke control knob all the way in.
• Pull starter handle to start the engine.
• When engine starts, immediately squeeze throttle trigger
to release throttle latch.
Open choke
Choke control knob
Chain brake
Start / Run
Ignition
switch
Chain brake
Starter handle
Choke
Choke control knob
Purge pump
CAUTION
Do not increase engine speed while chain brake is locked.
NOTE
If engine does not start after 5 pulls, repeat instructions.
NOTE
If engine does not start after 5 pulls, use cold start proce-
dure.

18
CS-310
RUNNING
WARNING
The saw chain should not move at idle, otherwise seri-
ous personal injury may result.
NOTE
If saw chain moves adjust carburetor according to
“Carburetor Adjustment” instructions in this manual, or
see your dealer.
• When engine starts, keep idling for a few minutes.
• Set the brake lever in the unlocked position before
starting to cut.
• Pull throttle trigger gradually and increase revolution of
the engine.
• The chain starts running when the engine reaches
4200 r/min approximately.
• Conrm proper acceleration and lubrication of chain
and bar. (Non-adjustable automatic oil pump)
• Do not run the engine at high speed unnecessarily.
• Be sure that saw chain stops moving when throttle trig-
ger is released.
STOPPING
• Release throttle trigger and move ignition switch down
to “STOP” position.
NOTE
If engine does not stop, pull choke control knob out
fully to stop engine.
Return the unit to your authorized ECHO dealer to
check and repair stop switch before starting the engine
again.
CHECKING CHAIN TENSION
•Chain tension should be checked frequently during
work and corrected as necessary.
CAUTION
Do not operate with a loose chain.
CHAIN LUBRICATION TEST
Holdthechainjustaboveadrysurfaceandopenthe
throttletohalfspeedfor30seconds.
Athinlineof“thrown”oilshouldbeseenonthedrysurface.
STOP
Ignition
switch
Throttle trigger
Unlock chain brake

19 CS-310
CUTTING INSTRUCTION
Kickback
GENERAL
CAUTION
•ReadtheECHO“CHAINSAWSAFETYMANUAL”includedwith
yourchainsawforadditionalcuttingandsafetyinstructions.
•Wearsuitablehearingprotectionsuchasearmuffsorearplugs
toprotectagainstobjectionableoruncomfortableloudnoises.
•Donotletthetipofthebartouchanythingwhile
the engine is running. At cutting speed the chain is
moving at a high rate of speed. Should the tip contact
a limb or log while the chain is moving, the tip will be
pushed upward with considerable force.
This is known as kickback. Avoid it!
Inallcircumstancestheoperationofthechainsawisaone-man
job.
Itisdifcultattimestotakecareforyourownsafety,sodon’tas-
sumetheresponsibilityforahelperaswell.
Afteryouhavelearnedthebasictechniquesofusingthesaw,your
bestaidwillbeyourowngoodcommonsense.
Theacceptedwaytoholdthesawistostandtotheleftofthesaw
withyourlefthandonthefronthandlebarandyourrighthandon
therearhandlesoyoucanoperatethethrottletriggerwithyour
rightindexnger.
Beforeattemptingtofellatree,cutsomesmalllogsorlimbs.
Becomethoroughlyfamiliarwiththecontrolsandtheresponses
of the saw.
Starttheengine,seethatitisrunningproperly.
Squeezethetriggertoopenthethrottlewideopenandstartthe
cut.Ifthechainisproperlysharpened,thecuttingshouldberela-
tivelyeffortless.
Itisnotnecessarytopressdownhardtomakethesawcut.
Pushingthesawtoohardwillslowtheengineandcuttingwill
actuallybemoredifcult.
Somematerialmayadverselyaffectthehousingsofyourchain
saw.
(ExamplepalmTreeAcid,fertilizeretc.)
Toavoidhousingdeterioration,carefullyremoveallpackedsaw-
dustaroundclutchandguidebarareaandwashwithwater.Coat
metalpartswithlightoil.
NOTE
Some material may adversely affect the housings of your
ECHO chain saw.
(Example: Palm Tree Acid, fertilizer, etc.) To avoid hous-
ing deterioration, carefully remove all packed saw dust
around clutch and guide bar area and wash with water.
Coat metal parts with light oil.

20
CS-310
FELLING THE TREE
1
2
3
Felling cut
Hinge
Direction of fall
First cut
Notch
Second cut
One-third tree diameter
Direction of fall
5 cm (2 in.)
5 cm (2 in.)
45°
Not this way
Retreat
Retreat
3 m (10 feet)
WARNING
A falling tree can seriously damage anything it may
hit - a car, a house, a fence, a power line, or another
tree. There are ways to make a tree fall where you
want it, so rst decide where that is!
A falling tree can seriously damage anything it may hit - a
car, a house, a fence, a power-line, or another tree.here
are ways to make a tree fall where you want it, so rst
decide where that is!
Before cutting, clear the area around the tree.
You will need good footing while working and you should
be able to work the saw without hitting any obstacles.
Next, select a path of retreat.
When the tree begins to fall you should retreat away from
the direction of fall at a 45-degree angle and at least 3
m (10 feet) from the trunk to avoid the trunk kicking back
over the stump.
Begin the cut on the side to which the tree is to fall. Cut
a notch about 1/3 of the way into the tree. The position of
this notch is important since the tree will try to fall “into”
the notch.
The felling cut is made on the side opposite the notch
and at a level about 5 cm (2 in.) above the bottom of the
notch.
Do not try to cut through to the notch with the felling cut.
The remaining wood between the notch cut and felling
cut about 5 cm (2 in.) will act as a hinge when the tree
falls, guiding it in the desired direction.
When the tree starts to fall, kill the engine, place the saw
on the ground and make your retreat quickly.
To fell big trees with a diameter exceeding twice the bar
length, start the notching cuts from one side and draw
the saw through to the other side of the notch.
Start the back cut on one side of the tree, pivoting the
saw through to form the desired hinge on that side.
Then remove the saw for the second cut. Insert the saw
in the rst cut, very carefully so as not to cause kickback.
The nal cut is made by drawing the saw forward in the
cut to reach the hinge.