Echo CS-310 User manual

X7503270006
05/13
Chain Saw
Instruction Manual
MODEL : CS-310
WARNING
Users of this equipment risk injury to themselves and others if the unit is used improperly
and/or safety precautions are not followed. ECHO provides an operator’s manual and a
safety manual. Both must be read and understood for proper and safe operation. Failure to
do so could result in serious injury.

2
CS-310
CONTENTS
CONTENTS.............................................................................................................. 2
PACKING LIST......................................................................................................... 3
RULES FOR SAFE OPERATION ............................................................................ 4
KICKBACK SAFETY PRECAUTIONS FOR CHAIN SAW USERS.......................... 4
CORRECT USE OF CHAIN BRAKE........................................................................ 5
AUTOMATIC CHAIN BRAKE ................................................................................... 6
Other Safety Precautions ......................................................................................... 6
OPERATOR SAFETY .............................................................................................. 8
SYMBOLS AND SIGNS ........................................................................................... 9
DECALS ................................................................................................................... 10
EMISSION DATA ..................................................................................................... 10
DESCRIPTION OF PARTS...................................................................................... 11
PREPARATION FOR USE....................................................................................... 13
FUEL AND LUBRICANT .......................................................................................... 15
OPERATION ............................................................................................................ 17
CUTTING INSTRUCTIONS...................................................................................... 20
CHAIN AND GUIDE BAR COMBINATION............................................................... 23
MAINTENANCE AND CARE.................................................................................... 24
Carburetor Adjustment......................................................................................... 25
High Altitude Operation........................................................................................ 25
SETTING THE SAW CHAIN .................................................................................... 29
TROUBLESHOOTING ............................................................................................. 31
STORAGE AFTER USE........................................................................................... 32
TECHNICAL DATA................................................................................................... 33
WARRANTY STATEMENTS.................................................................................... 34
SERVICING INFORMATION.................................................................................... 36
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.
Copyright© 2013 By Echo, Incorporated
All Rights Reserved.

3CS-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.
Warranty registration
card
Assembly Tool (s)
ECHO Power Blend X™
2-stroke oil sample
Instruction manual Safety manual
ECHO chain saw
Saw chain
Guide bar
Kick Guard®
Emission Control Warranty
Statement

4
CS-310
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, Kicking 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 rapidly 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 recommended 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.
Linear kickback
Rotational kickback
Chain moving downward at impact
Kickback
Kickback
Danger Zone
Rotational kickback
RULES FOR SAFE OPERATION
Kickback Safety Precautions for Chain Saw Users
Pinch

5CS-310
Chain brake function
When the lever is pushed forward, chain brake
instantly stops the chain.
Chain brake unlock
When the lever is fully pulled, toward the
operator, brake is unlocked.
CHAIN BRAKE OPERATION
• Set the lever in the unlocked position before starting to
cut.
• If the brake is tripped by kickback reaction, the chain
will stop immediately. Release the throttle to avoid pos-
sible damage to the engine or clutch.
• Do not attempt to operate the engine with the brake
locked.
TESTING THE BRAKE
• Start the engine on a solid level surface and run at a
fast idle until warm.
• Hold the saw rmly by the handles and accelerate the
engine to a fast idle.
• Slowly operate the chain brake lever while holding the
saw rmly on the ground. When the brake lever trips,
the chain should stop. Immediately release the throttle
trigger.
IMPORTANT
Do not allow the saw to tip forward in order to avoid
damage to the chain.
WARNING
If the chain does not stop immediately, return the saw
to your authorized ECHO dealer for repair.
NOTE
• For practice, while cutting a small tree, push the
lever forward to lock the brake.
• Conrm that the brake works properly before each
use.
• If the chain brake is clogged with wood chips, func-
tion of the brake may deteriorate. Always keep the
device clean.
• Do not increase engine RPM's while the chain brake
is locked.
CORRECT USE OF CHAIN BRAKE
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 fol-
lows.
USA : ANSI Standard B175.1
Safety Requirement for chain saws
WARNING
ANSI Standard B175.1 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.

6
CS-310
End of the guide bar may be placed at the
height of about 35 cm (14 in.).
35 cm
(14 in.)
AUTOMATIC CHAIN BRAKE
Kickback produced from the tip of the guide bar will trip
the automatic chain brake. To make sure that the auto-
matic chain brake operates properly, follow these steps:
1. Stop the engine.
2. Hold the saw with the guide bar approximately 35 cm
(14 in.) above a wooden surface. Right hand should
hold the rear handle, and left hand should hold the
front handle.
3. Release the front handle and drop the end of the
guide bar against the wooden surface.
4. The impact should lock the chain brake.
IMPORTANT
When checking the operation of the automatic chain
brake, use a soft surface substance like wood to
provide the impact so the chain is not damaged.
Rear handle should be gripped lightly with the
right hand.
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.
Other Safety Precautions
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.

7CS-310
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.
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.

8
CS-310
VIBRATION AND COLD
• It is believed that a condition called Raynaud’s Phe-
nomenon, which affects the ngers of certain individu-
als, 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 recommended because the minimum expo-
sure 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 swelling 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 shoulders 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 develop-
ing 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 re-
petitive movement.
• Do exercises to strengthen hand and arm muscles.
• 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 require-
ments have the mark “Z 87” stamped on them.
• Wear hearing protection. If this guideline is not fol-
lowed, 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. Re-
tain hair with cap or net.
HOT HUMID WEATHER
• Heavy protective clothing can increase operator fa-
tigue 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 seri-
ous property damage or personal injury may result.
OPERATOR SAFETY
WARNING
The ignition components of this machine generate an electromagnetic eld during operation which may interfere
with some pacemakers. To reduce the risk of serious or fatal injury, persons with pacemakers should consult
with their physician and the pacemaker manufacturer before operating this machine. In the absence of such
information, ECHO does not recommend the use of ECHO products by anyone who has a pacemaker.

9CS-310
SYMBOLS AND SIGNS
WARNING
The safety alert symbol accompanied by
the word “WARNING” calls attention to an
act or condition which CAN lead to serious
personal injury or death 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
The safety alert symbol accompanied by
the word “CAUTION” calls attention to an
act or condition 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
The safety alert symbol accompanied by
the word “DANGER” calls attention to an
act or condition which WILL lead to serious
personal injury or death if not avoided.
Carburetor adjustment
- Idle speed
Carburetor adjustment
- High speed mixture
WARNING!!
Read and follow all safety
precaution in the instruction
manual. Failure to follow
instructions could result in
serious personal injury.
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
Emergency stop
Choke control “Cold Start”
position (choke closed)
Contact of the guide bar tip
with any object should be
avoided
Tip contact may cause the
guide bar to move suddenly
upward and backward, which
may cause serious injury
Both of the operator’s hands
must be used to operate the
chain saw
Chain oiler adjustment
Purge pump
Hot surface
Chain oil ll
STOP

10
CS-310
DECALS
Locate these safety decals on your unit. Make sure
the decals are legible and that you understand and
follow the instructions on them. If a decal can-
not be read, a new one can be ordered from your
ECHO dealer.
WARNING!! Read and follow all
safety precaution in the instruction
manual. Failure to follow
instructions could result in serious
personal injury.
CS-310 REPLACEMENT BAR AND CHAIN
GUIDE BAR* CHAIN*
PART NO. TYPE LINKS
12” 12A0CD3745 OREGON 91PX 45
14” 14A0CD3752 OREGON 91PX 52
16” 16A0CD3757 OREGON 91PX 57
Note: There may be other replace-
ment components for achieving
kickback protection. For details,
please refer to the chain and bar
combination sheet shown in the
instruction manual.
EmISSION DATA
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 50 or 300 hour emission compliance period is the time span selected by the manufacturer certifying
the engine emissions output meets applicable emissions regulations, provided that approved mainte-
nance procedures are followed as listed in the Maintenance Section of this manual.
EmISSION CONTROL (ExHAUST &EvAPORATIvE)
EPA 2010 and Later and/or C.A.R.B. TIER III
The emission control system for the engine is EM (en-
gine modication) and, if the second to last character
of the Engine Family on the Emission Control Informa-
tion label (sample below) is “C”, “K”, or “T”, the emis-
sion control system is EM and TWC (3-way catalyst).
The fuel tank/fuel line emission control system is EVAP
(evaporative emissions). Evaporative emissions for
California models are only applicable to fuel tanks.

11 CS-310
DESCRIPTION OF PARTS
2
1
6
5
9
8
11
12
13
4
10
7
3
14
22
21
19 18 17
16
15
23
20

12
CS-310
DESCRIPTION OF PARTS
1. Instruction manual - Included with unit. Read
before operation and keep for future reference to
learn proper, safe operating techniques.
2. Safety manual - Describe operating and safety
instructions for this chain saw.
3. Chain Brake Lever/Front hand guard -Locks and
unlocks the chain brake to stop or allow saw chain
rotation. Guard between the front handle and the
saw chain helps protect the hand from injuries if
the hand slips off the front handle.
4. Spark arrestor mufer or spark arrestor muf-
er with catalyst -The mufer or catalytic mufer
controls exhaust noise and emission. The spark
arrestor screen prevents hot, glowing particles of
carbon from leaving the mufer. Keep exhaust area
clear of ammable debris.
5. Bar tip guard - Anti-kickback device attached on
the bar nose.
6. Saw chain - Chain, serving as a cutting tool.
7. Guide bar - The part that supports and guides the
saw chain.
8. 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.
9. Chain tension adjuster - Device to adjust chain
tension.
10. Clutch cover - Protective cover for the guide bar,
saw chain, clutch and sprocket when the chain saw
is in use.
11. Rear hand guard - Extension on the lower part of
the rear handle for protecting the hand from the
chain if it breaks or degrooves.
12. Purge pump - When starting engine, push purge
pump 3 or 4 times.
13. Choke control knob - Device for enriching the
fuel/air mixture in the carburetor to aid cold starting
Also activates fast idle throttle latch.
14. Cylinder cover - The cooling airow grill. It covers
the cylinder, air lter, spark plug and silencer.
15. Throttle trigger 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.
16. Rear handle (for the right hand) - Support han-
dle located towards the rear of the engine housing.
17. Throttle trigger - Device activated by the opera-
tor’s nger, for controlling the engine speed. Also
releases fast idle throttle lock when squeezed
and released immediately after starting engine.
18. Ignition switch - Device for connecting and dis-
connecting the ignition system and thus allowing
the engine to be started or stopped.
19. Fuel tank cap - For closing the fuel tank.
20. Cylinder cover latch - Secures cylinder cover.
21. Starter handle - Pull handle slowly until starter
engages then quickly and rmly. When engine
starts, return handle slowly. DO NOT let handle
snap back or damage to unit will occur.
22. Front handle (for the left hand) - Support handle
located at the front of the engine housing.
23. Oil tank cap - For closing the oil tank.
CHAIN SAW TERMS
1. Fast Idle - Throttle setting that causes engine to
operate at a faster speed for easier starting.
2. Throttle Latch - Device that sets idle speed to fast
idle when choke control is operated.
3. Chain Brake - Stops the saw chain.
4. Drive Sprocket - Drives saw chain.
5. Clutch - Turns drive sprocket when engine rpm is
fast enough to provide the power needed for cutting.

13 CS-310
PREPARATION FOR USE
(A)
(D)
(E)
(C)
(B)
(F)
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.
KICK GUARD®TO BAR INSTRUC-
TIONS
Tools Needed: Two 11 mm (7/16 in.) Wrenches.
For saws with Kick Guard®P/N 2894901 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.
Clutch cover
Two nuts
Guide bar
adjuster
hole
Clutch cover
Nuts
Adjuster pin
Clutch Guide bar studs
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 “Main-
tenance and Care” section for guide bar/saw chain
maintenance procedures.
NOTE
• Move the chain brake lever (Front Hand Guard)
fully rearward to remove or install the clutch cover
to chain saw.
• Align the brake connector of the clutch cover to the
groove on the side of the brake lever.

14
CS-310
5. 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.
6. 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
NOTE
All chains require frequent adjustments.
Guide bar
adjuster
hole
Clutch cover
Nuts
Adjuster pin
Clutch Guide bar studs

15 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.
FUEL AND LUBRICANT
NOTE: Use of unmixed, improperly mixed, or fuel older than 90 days, (stale fuel), may cause hard starting, poor
performance, or severe engine damage and void the product warranty. Read and follow instructions in the Stor-
age section of this manual.
FUEL STATEmENT
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 approved.
Two Stroke Oil - A two-stroke engine oil meeting ISO-L-EGD (ISO/CD 13738) and J.A.S.O. FD Standards must be
used. Echo brand premium Power Blend XTM Universal 2-Stroke Oil meets these standards. Engine problems due to
inadequate lubrication caused by failure to use an ISO-L-EGD (ISO/CD 13738) and J.A.S.O. 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.

16
CS-310
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.
Mixing Instructions
1. Fill an approved fuel container with half of the re-
quired 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 con-
tainer. Store in a well-ventilated, unoccupied building,
away from sparks and ames.
Fuel Mix Chart
50:1
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 mini-
mum 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 various 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 resinous
trees.
• When refueling, also rell chain oil.

17 CS-310
OPERATION
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. This unit is equipped with a spark arrestor to
prevent discharge of hot particles from the engine. Metal blade use also can create sparks if the blade strikes
rocks, metal, or other hard objects. Contact local re authorities for laws or regulations regarding re prevention
requirements.
Start / Run
Ignition
switch
Chain brake
Choke
Choke control knob
Purge pump
WHEN THE ENGINE IS COLD
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.
• 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 posi-
tion)
NOTE
Do not pull starter rope out to the maximum possible
position.
Do not allow recoil handle to snap back against the
casing.
WARNING
• After choke control knob is pulled and then knob is
returned to original position, throttle remains slightly
open (fast idle latch condition).
• The chain will attempt to move when engine is
started with fast idle throttle latch engaged.
• Do not start engine before chain brake is locked.

18
CS-310
Chain brake
Starter handle
• 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.
CAUTION
• After starting the engine, immediately squeeze
and then release throttle trigger to release fast idle
throttle latch, otherwise severe brake damage may
occur.
• Never use fast idle throttle latch for cutting.
• Use the fast idle throttle latch only in starting.
NOTE
If engine does not start after 5 pulls, repeat
instructions.
NOTE
Do not increase engine speed while chain brake is
locked. Severe brake damage will result.
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, squeeze throttle trigger to release choke and return
engine to idle.
NOTE
If engine does not start after 5 pulls, repeat instruc-
tions.
NOTE
Do not increase engine speed while chain brake is
locked. Severe brake damage will result.
Open choke
Choke control knob
Open choke
Choke control knob

19 CS-310
RUNNING
WARNING
The saw chain should not move at idle, otherwise serious
personal injury may result.
NOTE
If saw chain moves adjust carburetor according to “Carbu-
retor Adjustment” instructions in this manual, or see your
dealer.
• When engine starts, immediately squeeze and release
throttle trigger to release fast idle throttle latch, otherwise
severe brake damage will result.
• Keep idling for a few minutes.
• Set the brake lever in the unlocked position before starting
to cut.
• Squeeze 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 trigger is
released.
STOPPING
• Release throttle trigger and allow engine to idle.
• 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

20
CS-310
CUTTING INSTRUCTIONS
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.
Kickback
GENERAL
CAUTION
• Read the ECHO “CHAIN SAW SAFETY MANUAL”
included with your chain saw for additional cutting and
safety instructions.
• Wear suitable hearing protection such as earmuffs or
earplugs to protect against objectionable or uncomfortable
loud noises.
• 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 assume 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 relatively 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.