Troy-Bilt AS720 User Manual

769-09332 / 00 09/13

Straight-Shaft Extended-Reach

Trimmer Attachment

TABLE OF CONTENTS

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Know Your Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Cleaning and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

All information, illustrations, and specifications in this manual are based
on the latest product information available at the time of printing. We
reserve the right to make changes at any time without notice.

Copyright© 2013 MTD SOUTHWEST INC, All Rights Reserved.

SAVE THESE INSTRUCTIONS

SERVICE

Operator’s Manual

DO NOT RETURN THIS UNIT TO THE RETAILER. PROOF OF
PURCHASE WILL BE REQUIRED FOR WARRANTY SERVICE.

For assistance regarding the assembly, controls, operation or
maintenance of the unit, please call the Customer Support Department
at 1-800-800-7310 in the United States or 1-800-668-1238 in Canada.
Additional information about the unit can be found on our website:
www.mtdproducts.com (U.S.) or www.mtdproducts.ca (Canada).

For service, please call the Customer Support Department to obtain
a list of authorized service dealers near you. Service on this unit,
both within and after the warranty period, should only be performed
by an authorized and approved service dealer. When servicing, use
only identical replacement parts.

IMPORTANT: Read this manual thoroughly before using this product. Follow all instructions.

READ ALL INSTRUCTIONS BEFORE OPERATING

• Carefully read and understand the operator's manual of the unit
that powers this attachment.

• Read the instructions carefully. Be familiar with the controls and
proper use of the unit.

• Do not operate this unit when tired, ill or under the influence of
alcohol, drugs or medication.

• Children must not operate the unit. Teens must be accompanied
and guided by an adult.

• All guards and safety attachments must be installed properly
before operating the unit.

• Inspect the unit before use. Replace damaged parts. Check for
fuel leaks. Make sure all fasteners are in place and secure.
Replace parts that are cracked, chipped, or damaged in any
way. Do not operate the unit with loose or damaged parts.

• Carefully inspect the area before starting the unit. Remove all
debris and hard or sharp objects such as glass, wire, etc.

• Only use the trimming line described in the Specifications section
of this manual. Never use metal-reinforced line, wire, chain or
rope. These can break off and become dangerous projectiles.

• Be aware of the risk of injury to the head, hands and feet.

• Clear the area of children, bystanders and pets; keep them
outside a 50-foot (15 m) radius, at a minimum. Even then, they are
still at risk from thrown objects. Encourage bystanders to wear
eye protection. If you are approached, stop the unit immediately.

SAFETY WARNINGS FOR GAS UNITS

• Store fuel only in containers specifically designed and approved
for the storage of such materials.

• Always stop the engine and allow it to cool before filling the
tank. Never remove the fuel tank cap or add fuel when the
engine is hot. Always loosen the fuel tank cap slowly to relieve
any pressure in the tank before fueling.

• Always mix and add fuel in a clean, well-ventilated outdoor area
where there are no sparks or flames. DO NOT smoke.

• Never operate the unit without the fuel cap securely in place.

• Avoid creating a source of ignition for spilled fuel. Wipe up any
spilled fuel from the unit immediately, before starting the unit.
Move the unit at least 30 ft. (9.1 m) from the fueling source and
site before starting the engine. DO NOT smoke.

• Never start or run the unit inside a closed room or building.
Breathing exhaust fumes can kill. Operate this unit only in a well­ventilated outdoor area.

• IMPORTANT SAFETY INSTRUCTIONS •

SAFETY

SYMBOL MEANING

WARNING:Signals a SERIOUS hazard.

Failure to obey a safety WARNING signal CAN result in
serious injury to yourself or to others.

CAUTION:

Signals a MODERATE hazard.

Failure to obey a safety CAUTION signal MAY result in
property damage or injury to yourself or to others.

The purpose of safety symbols is to attract your attention to
possible dangers. The safety symbols, and their explanations,
deserve your careful attention and understanding. The safety
warnings do not by themselves eliminate any danger. The
instructions or warnings they give are not substitutes for proper
accident prevention measures.

NOTE: Advises you of information or instructions vital to the

operation or maintenance of the equipment.

DANGER:Signals an EXTREME hazard.

Failure to obey a safety DANGER signal WILL result in
serious injury or death to yourself or to others.

WARNING:

When using the unit, all safety
rules must be followed. Please read these instructions
before operating the unit in order to ensure the safety of
the operator and any bystanders. Please keep these
instructions for later use.

WARNING:

Gasoline is highly flammable and
its vapors can explode if ignited. Take the following
precautions:

2

Read the operator’s manual and follow all warnings and safety
instructions. Failure to do so can result in serious injury to the
operator and/or bystanders.

WHILE OPERATING

• Wear safety glasses or goggles that meet current ANSI / ISEA
Z87.1 standards and are marked as such. Wear ear/hearing
protection when operating this unit. Wear a face or dust mask if
the operation is dusty.

• Wear heavy long pants, boots, gloves and a long sleeve shirt. Do
not wear loose clothing, jewelry, short pants, sandals or go
barefoot. Secure hair above shoulder level.

• The cutting head shield must always be in place while operating
the unit. Do not operate the unit without both trimming lines
extended and the proper line installed. Do not extend the
trimming line beyond the length of the shield.

• Adjust the handle to provide the best grip, if applicable.

• Make sure the attachment is not in contact with anything before
starting the unit.

• Use the unit only in daylight or good artificial light.

• Use the right tool. Only use this tool for its intended purpose.

• Always hold the unit with both hands when operating. Keep a
firm grip on both handles or grips.

3

SAFETY WARNINGS FOR ELECTRIC UNITS

• CORD SETS: Make sure your cord set is in good condition.
When using a cord set, be sure to use a cord that is heavy
enough to carry the current that your unit will draw. An
undersized cord set will cause a drop in line voltage resulting in
loss of power and overheating. See the operator’s manual for
the unit that will power this attachment for the recommended
cord size.

• Inspect all extension cords and the unit power connection
periodically. Look closely for deterioration, cuts or cracks in the
insulation. Also inspect the connections for damage. Replace
the cords if any defects or damage appear.

• Prevent disconnection of the power head from the extension
cord during operation by using a plug-receptacle retaining strap,
connector, or by making a knot (Fig. A).

• Avoid dangerous environments. Never operate your unit in damp
or wet conditions. Moisture is a shock hazard.

• Do not use the unit in the rain. Do not use in or around water.

• Do not handle the plug or unit with wet hands or standing on
any wet surfaces.

• Do not leave the unit plugged in when not in use, changing
attachments or while being serviced.

WARNING:

To reduce the risk of electrical shock, use
only extension cords approved for outdoor use, such as an
extension cord of cord type SW-A, SOW-A, STW-A, STOW­A, SJW-A, SJOW-A, SJTW-W or SJTOW-A. Extension
cords are available from your local retailer. Use only round­jacketed extension cords approved for outdoor use.

Fig. A

Unit Power Cord

Extension Cord

• Do not overreach. Always keep proper footing and balance. Take
extra care when working on stairs, steep slopes or inclines. To
avoid serious injury, do not operate the unit while on a ladder or
a roof.

• Keep hands, face, and feet away from all moving parts. Do not
touch or try to stop moving parts.

• Do not operate the unit faster than the speed needed to do the job.
Do not run the unit at high speed when not in use.

• Do not force the unit. It will do a better, safer job when used at
the intended rate.

• Always stop the unit when operation is delayed or when walking
from one location to another.

• If you strike or become entangled with a foreign object, stop the
unit immediately and check for damage. Do not operate before
repairing damage. Do not operate the unit with loose or
damaged parts.

• Use only original equipment manufacturer (OEM) replacement
parts and accessories for this unit. These are available from your
authorized service dealer. Use of any other parts or accessories
could lead to serious injury to the user, or damage to the unit,
and void the warranty.

• Keep the unit clean. Carefully remove vegetation and other
debris that could block moving parts.

• If the unit starts to vibrate abnormally, stop the unit immediately.
Inspect the unit for the cause of the vibration. Vibration is
generally an indicator of trouble.

OTHER SAFETY WARNINGS

• Maintain the unit with care.

• All service, other than the maintenance procedures described in
this manual, should be performed by an authorized service dealer.

• Never remove, modify or make inoperative any safety device
furnished with the unit.

• Before inspecting, maintaining, cleaning, storing, transporting or
replacing any parts on the unit:

1. Stop the unit.

2. Make sure all moving parts have stopped.

3. Allow the unit to cool.

4. For gas-powered units, disconnect the spark plug wire. For
electric-powered units, disconnect the unit from the power
source.

• Secure the unit while transporting.

• Never store the unit with fuel in the tank, inside a building where
fumes may reach an open flame (pilot lights, etc.) or sparks
(switches, electrical motors, etc.).

• Store the unit in a dry place, secured or at a height to prevent
unauthorized use or damage. Keep the unit out of the reach of
children.

• Never douse or squirt the unit with water or any other liquid.
Keep handles dry, clean and free from debris. Clean the unit
after each use. Refer to Cleaning and Storage. Do not use
solvents or strong detergents.

• Keep these instructions. Refer to them often and use them to
instruct other users. If you loan this unit to others, also loan
them these instructions.

SAVE THESE INSTRUCTIONS

• SAFETY & INTERNATIONAL SYMBOLS •

This operator's manual describes safety and international symbols and pictographs that may appear on this product. Read the operator's
manual for complete safety, assembly, operating and maintenance and repair information.

SYMBOL MEANING SYMBOL MEANING

• SAFETY ALERT SYMBOL

Indicates danger, warning or caution. May be used in
conjunction with other symbols or pictographs.

• READ OPERATOR'S MANUAL

WARNING:Read the operator’s

manual(s) and follow all warnings and safety
instructions. Failure to do so can result in serious
injury to the operator and/or bystanders.

• WEAR EYE AND HEARING PROTECTION

WARNING:Thrown objects and loud

noise can cause severe eye injury and hearing loss.
Wear eye protection meeting current ANSI / ISEA
Z87.1 standards and ear protection when operating
this unit. Use a full face shield when needed.

•

THROWN OBJECTS AND ROTATING CUTTER CAN
CAUSE SEVERE INJURY

WARNING:

Small objects can be
propelled at high speed, causing injury. Keep away
from the rotating rotor.

• KEEP BYSTANDERS AWAY

WARNING:

Keep all bystanders,
especially children and pets, at least 50 feet (15 m)
from the operating area.

• SHARP BLADE

WARNING:

Sharp blade on trimmer
attachment shield. To prevent serious injury, do not
touch the line cutting blade.

4

Hanger Cap

Shaft Housing

Cutting Head Shield

Line Cutting Blade

Cutting Head

5

KNOW YOUR UNIT

APPLICATIONS

As a trimmer:

• Cutting grass and light weeds.

• Edging

• Decorative trimming around trees, fences, etc.

ASSEMBLY TOOLS REQUIRED:

• #2 Phillips screwdriver

SPECIFICATIONS*

* All specifications are based on the latest product information available at the time of printing. We reserve the right to make changes at any
time without notice.

Approximate Unit Weight (attachment only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4 lbs. (1.4 - 1.8 kg)

Trimmer Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fixed-line cutting head

Trimming Line Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.105 in. (2.67 mm) pre-cut twist line

Cutting Path Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 in. (40.64 cm)

ASSEMBLY

6

INSTALLING THE CUTTING HEAD SHIELD

1. Place the cutting head shield onto the mount bracket. Align the
holes in the cutting head shield with the holes in the mount
bracket. (Fig. 1)

2. Screw the 2 screws through the mount bracket and into the
cutting head shield until finger tight.

3. Using a #2 Phillips screwdriver, tighten the screws until the
cutting head shield is firmly in place. Tighten the screws equally.
The gap between the mount bracket and the cutting head shield
should be the same on each side.

WARNING:

To prevent serious personal injury, never

operate the unit without the cutting head shield in place.

Fig. 1

Mount Bracket

Cutting Head Shield

Screws (2)

7

OPERATING THE COUPLER

The coupler enables the use of various optional attachments.

Installing the Attachment

1. Remove the hanger cap from the attachment. Keep the hanger
cap for use when storing the attachment. If present, remove the
gray spacer from the coupler.

2. Set the unit on a flat, level surface.

3. Turn the knob counterclockwise to loosen the coupler (Fig. 3).

4. Align the release button with the guide recess (Fig. 4).

5. Push the attachment straight into the coupler until the release
button snaps firmly into the primary hole (Fig. 4).

6. Turn the knob clockwise to tighten the coupler (Fig. 3).

NOTE: Do not tighten the nut (Fig. 4).

Removing the Attachment

1. Set the unit on a flat, level surface.

2. Turn the knob counterclockwise to loosen the coupler (Fig. 3).

3. Press and hold the release button (Fig. 4).

4. Pull the attachment straight out of the coupler (Fig. 2).

WARNING:

Before using any attachment, read and
understand the manual that came with the attachment.
Follow all safety information contained within.

CAUTION:

Before operating the unit, make sure the
release button is fully snapped into the primary hole and
the knob is securely tightened.

WARNING:

To avoid serious personal injury and
damage to the unit, shut the unit off before removing or
installing an attachment.

CAUTION:

The release button should be snapped into
the primary hole only. Using the wrong hole could lead to
personal injury or damage to the unit.

Fig. 3

Fig. 4

Fig. 2

Coupler

Attachment

Release Button

Guide Recess

Knob

Primary Hole

Nut

Tighten Loosen

8

OPERATION

HOLDING THE UNIT

• Stand in the operating position (Fig. 5). Stand up straight. Do not
bend over.

• Keep feet apart and firmly planted.

• Hold the shaft grip with the right hand. Keep the right arm
slightly bent.

• Hold the handle with the left hand. Keep the left arm straight.

• Hold the unit at waist level.

• Position the cutting head a few inches above the ground.

WARNING:

Always wear eye, hearing, hand, foot and
body protection to reduce the risk of injury when operating
this unit.

TIPS FOR BEST RESULTS

• To direct clippings away from the operator, tilt the cutting head
slightly down to the right; cut from left to right whenever possible.

• Do not trim wet grass or weeds.

NOTE: Some line breakage will occur from:

• Entanglement with foreign matter

• Normal line fatigue

• Attempting to cut thick vegetation

• Forcing the line into objects such as walls or fence posts

DECORATIVE TRIMMING

When trimming around trees, posts, fences, etc., rotate the whole
unit so that the cutting head is at a 30° angle to the ground (Fig. 6).

Fig. 5

Fig. 6

9

MAINTENANCE

WARNING:

To prevent serious injury, never perform
maintenance or repairs while the unit is running. Always
allow the unit to cool before servicing or repairing the unit.
For gas-powered units, disconnect the spark plug wire to
prevent the unit from starting accidentally. For electric­powered units, disconnect the unit from the power source
to prevent the unit from starting accidentally.

NOTE: Some maintenance procedures may require special tools or

skills. If you are unsure about these procedures, take the unit to
an MTD authorized service dealer.

Fig. 7

Fig. 8

Fig. 9

Line

Holes

Cutting Head

Positioning

Tunnel

Positioning

Tunnel

Line

Line

Line

Cutting Head

Line

REPLACING THE TRIMMING LINE

Only use the trimming line described in the Specifications section.
Other types of trimming line may cause the unit to overheat or fail.

1. Remove the old line from the cutting head.

2. Use a clean cloth to clean the surface of the cutting head.

3. Insert the ends of the line through the circular holes in the side
of the cutting head (Fig. 7). Push the line through the holes until
both ends protrude from the positioning tunnels (Fig. 8).

4. Pull the ends of the line until the line is tight against the cutting
head. Make sure the ends of the line are of equal length (Fig. 9). If
one end is longer than the other, push the longer end back
through the cutting head partway and pull the shorter end out. If
necessary, repeat this process until both ends are of equal length.

5. Press the exposed trimming line between the circular holes until
it lies flat against the cutting head (Fig. 9).

WARNING:

Never use metal-reinforced line, wire, chain or

rope. These can break off and become dangerous projectiles.

10

CLEANING AND STORAGE

CLEANING

Use a small brush or clean, dry cloth to clean the outside of the unit.

WARNING:

To avoid serious personal injury, always stop
the unit and allow it to cool before cleaning or maintaining
the unit.

STORAGE

• Never store a fueled unit where fumes may reach an open flame
or spark.

• Allow the unit to cool.

• Thoroughly clean the unit and inspect it for any loose or
damaged parts. Replace damaged parts and tighten loose
screws, nuts or bolts.

• Lock up the unit to prevent unauthorized use or damage.

• Store the unit indoors, in a dry, well-ventilated area.

• Store the unit out of the reach of children.

• To suspend the attachment from a hook, install the hanger cap
onto the attachment. Make sure the release button is securely
locked into one of the holes on the hanger cap.

WARNING:

Do not use strong detergents. Household
cleaners that contain aromatic oils such as pine and lemon,
and solvents such as kerosene, can damage plastic.