Ryobi 790r User guide

FOR QUESTIONS, CALL 1-800-345-8746 in U.S. or

1-800-265-6778 in CANADA

www.ryobi.com

IMPORTANT MANUAL DO NOT THROW AWAY

OPERATOR’S MANUAL

2-Cycle Gas Trimmer/Brushcutter

780r–790r

THANK YOU

Thank you for buying this quality product. This
modern outdoor power tool will provide many
hours of useful service. You will find it to be a
great labor-saving device. This operator’s
manual provides you with easy-to-understand
operating instructions. Read the whole manual
and follow all the instructions to keep your new
outdoor power tool in top operating condition.
The other manual that came with your power
tool, the parts manual, contains all the
information that you need to order parts.

PRODUCT REFERENCES,
ILLUSTRATIONS AND
SPECIFICATIONS

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© 1998 Ryobi Outdoor Products, Inc.
All Rights Reserved.

Click-Link® is a registered trademark of Ryobi
Outdoor Products.

Bump Head™ is a trademark of Ryobi Outdoor
Products.

SERVICE INFORMATION

Service on this unit both within and after the
warranty period should be performed only by
an authorized and approved service dealer.
Dial:

1-800-345-8746

in the United States or

1-800-265-6778

in Canada

to obtain the listing of the authorized service
dealer nearest you.

DO NOT RETURN THE UNIT TO THE
RETAILER.

NOTE: PROOF OF PURCHASE WILL BE

REQUIRED FOR WARRANTY
SERVICE.

Make sure this manual is carefully read and
understood before starting or operating this
equipment.

THIS PRODUCT IS COVERED BY ONE OR
MORE OF THE US PATENTS LISTED BELOW:
5,076,149; 4,901,682; 4,779,405; 4,651,422;
4,505,040; 4,463,498; 4,369,742; 4,342,236;
4,223,441; 2,125,688; D-249,012; D-239,329;

OTHER PATENTS PENDING.

INTRODUCTION

2

TABLE OF CONTENTS

I. California Emission Regulations . . . . . . . . 3

II. Rules for Safe Operation . . . . . . . . . . . 4-9

A. Important Safety Information . . . . . . .4-6

B. Safety and International Symbols . . .7-8

C. Know Your Unit . . . . . . . . . . . . . . . . . .9

III. Assembly Instructions . . . . . . . . . . . 10-14

A. Installing and Adjusting J-Handle . . . .10

B. Installing the Harness . . . . . . . . . . . . .11

C. Removing and Installing Cutting . . . . . .

Attachment Shield . . . . . . . . . . . . . . 11

D. Remove the Cutting Attachment and . . .

Install the Cutting Blade . . . . . . . .12-13

E. Remove the Cutting Blade and . . . . . . .

Install the Cutting Attachment . . . . . . .14

IV. Oil and Fuel Information . . . . . . . . . . . . . 15

V. Starting/Stopping Instructions . . . . . . . . 16

VI. Operating Instructions . . . . . . . . . . . 17-20

A. Operating Click-Link System (790r) . . .17

B. Holding the Trimmer . . . . . . . . . . . . . .18

C. Adjusting Trimming Line Length . . . . .18

D. Tips for Best Trimming Results . . . . . .19

E. Decorative Trimming . . . . . . . . . . . . . .19

F. Cutting Blade Operating Tips . . . . .19-20

VII. Maintenance and Repair Instructions .20-26

A. Maintenance Schedule . . . . . . . . . . . 20

B. Line Installation . . . . . . . . . . . . . . 21-22

C. Installing a Prewound Reel . . . . . . . . . 23

D. Air Filter Maintenance . . . . . . . . . . 23-24

E. Air Filter/Muffler Cover Removal . . . .23

F. Cleaning the Air Filter . . . . . . . . . . . . 24

G. Reinstalling the Air Filter/Muffler Cover 24

H. Carburetor Adjustment . . . . . . . . . . . 25

I. Replacing the Spark Plug . . . . . . . . . 26

J. Accessories/Replacement parts . . . . . 26

VIII. Cleaning and Storage . . . . . . . . . . . . . . 27

X. Troubleshooting Chart . . . . . . . . . . . . . . 28

XI. Specifications . . . . . . . . . . . . . . . . . . . . 29

XII. Warranty . . . . . . . . . . . . . . . . . . . . . .31-32

CONTENTS OF CARTON

This unit should consist of the following:

• Model 780r or Model 790r
Trimmer/Brushcutter
J-Handle and Hardware
Cutting Attachment Shield and Hardware
Blade with Cover and Hardware

• Bottle of 2-Cycle Oil

• Operator's Manual

• Parts Manual

• Product Registration Card

• Locking Rod

• Shoulder Strap

These items may be in the hardware bag or

assembled on your unit.

3

WARNING!

SPARK ARRESTOR

WARNING

CALIFORNIA EMISSION REGULATIONS

NOTE: For users on U.S. Forest Land and in the states of California, Maine, Oregon and Washington.

All U.S. Forest Land and the states of California (Public Resources Codes 4442 and 4443), Oregon and
Washington require, by law that certain internal combustion engines operated on forest brush and/or grass­covered areas be equipped with a spark arrestor, maintained in effective working order, or the engine be
constructed, equipped and maintained for the prevention of fire. Check with your state or local authorities for
regulations pertaining to these requirements. Failure to follow these requirements could subject you to liability
or a fine. This unit is not factory equipped with a spark arrestor. If these items are required in your area,
ask your LOCAL SERVICE dealer to install the Optional Accessory Part #180030 Spark Arrestor Kit.

FOR QUESTIONS, CALL 1-800-345-8746 IN U.S. OR 1-800-265-6778 in CANADA

California Proposition 65 Warning:

THE ENGINE EXHAUST FROM THIS

PRODUCT CONTAINS CHEMICALS

KNOWN TO THE STATE OF

CALIFORNIA TO CAUSE CANCER,

BIRTH DEFECTS OR OTHER

REPRODUCTIVE HARM.

This unit meets the 1995 to 1998 California emissions regulations for small off-road engines. These
units are identified by the label on the engine of your product. A typical identification label is shown.

To ensure that your unit continues to meet these regulations, refer to the following information and
instructions in this operator’s manual.

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.

RULES FOR SAFE OPERATION

4

• Clear the area to be cut before each use.
Remove all objects such as rocks, broken
glass, nails, wire, or string which can be
thrown or become entangled in the cutting
attachment. Clear the area of children,
bystanders, and pets. At a minimum, keep all
children, bystanders and pets outside a 50 ft.
(15 m.) radius; there still may be a risk to
bystanders from thrown objects. Bystanders
should be encouraged to wear eye
protection. If you are approached, stop the
engine and cutting attachment immediately.

• Squeeze the throttle control and check that it
returns automatically to the neutral position.
Make all adjustments or repairs before using
unit.

SAFETY WARNINGS FOR GAS
TRIMMERS

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

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

• Avoid creating a source of ignition for spilled
fuel. Do not start the engine until fuel vapors
dissipate.

READ ALL INSTRUCTIONS

BEFORE OPERATING

• 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 and teens under the age of 15 must
not use the unit, except for teens guided by
an adult.

• Inspect the unit before use. Replace
damaged parts. Check for fuel leaks. Make
sure all fasteners are in place and secure.
Replace cutting attachment parts that are
cracked, chipped, or damaged in any way.
Make sure the cutting attachment is properly
installed and securely fastened. Be sure the
cutting attachment shield is properly
attached, and positioned as recommended.
Failure to so can result in personal injury to
the operator and bystanders, as well as
damage to the unit

• Use only 0.095 in (2.41 mm) diameter
genuine Ryobi replacement line. Never use
metal-reinforced line, wire, or rope, etc..
These can break off and become a
dangerous projectile.

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

• IMPORTANT SAFETY INFORMATION •

DANGER: Failure to obey a safety

warning will result in serious injury
to yourself or to others.

Always
follow the safety precautions to
reduce the risk of fire, electric
shock, and personal injury.

WARNING: Failure to obey a safety
warning can result in injury to
yourself and others.

Always follow
the safety precautions to reduce the
risk of fire, electric shock, and
personal injury.

CAUTION: Failure to obey a safety
warning may result in property
damage or personal injury to
yourself or to others.

Always follow
the safety precautions to reduce the
risk of fire, electric shock, and
personal injury.

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.

SYMBOL MEANING

SAFETY ALERT SYMBOL:

Indicates danger, warning, or
caution. Attention is required in
order to avoid serious personal
injury. May be used in conjunction
with other symbols or pictographs.

NOTE: Advises you of information or

instructions vital to the operation or
maintenance of the equipment.

RULES FOR SAFE OPERATION

5

• Always stop the engine and allow it to cool
before filling the fuel tank. Never remove the
cap of the fuel tank, or add fuel, when the
engine is hot. Never operate the unit without
the fuel cap securely in place. Loosen the
fuel tank cap slowly to relieve any pressure in
the tank.

• Mix and add fuel in a clean, well-ventilated
area outdoors where there are no sparks or
flames. Slowly remove the fuel cap only after
stopping engine. Do not smoke while fueling
or mixing fuel. Wipe up any spilled fuel from
the unit immediately.

• Move the unit at least 30 ft. (9.1 m) from the
fueling source and site before starting the
engine. Do not smoke, keep sparks and
open flames from the area while adding fuel
or operating the unit.

WHILE OPERATING

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

• Wear safety glasses or goggles that are
marked as meeting ANSI Z87.1-1989
standards, and ear/hearing protection when
operating this unit. Wear a face or dust mask
if the operation is dusty. Long sleeve shirts
are recommended.

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

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

• This unit has a clutch. The cutting attachment
remains stationary when the engine is idling.
If it does not, have the unit adjusted by an
authorized service technician.

• Adjust the J-handle to your size to provide
the best grip.

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

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

• Avoid accidental starting. Be in the starting
position whenever pulling the starter rope.
The operator and unit must be in a stable
position while starting. See
Starting/Stopping Instructions.

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

• Do not overreach. Always keep proper
footing and balance.

• Always hold the unit with both hands when
operating. Keep a firm grip on both the front
and rear handle or grips.

• Keep hands, face, and feet at a distance
from all moving parts. Do not touch or try to
stop the cutting attachment when it is
rotating.

• Do not touch the engine or muffler. These
parts get extremely hot from operation.
When turned off they remain hot for a
short time.

• Do not operate the engine faster than the
speed needed to cut, trim or edge. Do not
run the engine at high speed when not
cutting.

• Always stop the engine when cutting is
delayed or when walking from one cutting
location to another.

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

• Stop and switch the engine to off for
maintenance, repair, or for changing the
cutting attachment or other attachments.

• Use only genuine Ryobi replacement parts
when servicing this unit. These parts are
available from your authorized service
dealer. Do not use parts, accessories or
attachments not authorized by Ryobi for this
unit. Doing so could lead to serious injury to
the user, or damage to the unit, and void
your warranty.

• Keep unit clean of vegetation and other
materials. They may become lodged
between the cutting attachment and shield.

• To reduce fire hazard, replace faulty muffler
and spark arrestor, keep the engine and
muffler free from grass, leaves, excessive
grease or carbon build up.

6

RULES FOR SAFE OPERATION

WHILE OPERATING WITH CUTTING
BLADE

• Read and understand all safety warnings
before operating this unit.

• Always use the shoulder harness when using
the brush blade accessory.

• Keep the handle between the operator
and cutting attachment or blade at all times.

• NEVER cut with the cutting blade located
over 30 inches (76 cm) or more above the
ground level.

• Blade thrust may occur when the spinning
blade contacts an object that it does not
immediately cut. Blade thrust can be violent
enough to cause the unit and/or operator to
be propelled in any direction , and possibly
lose control of the unit. Blade thrust can
occur without warning if the blade snags,
stalls or binds. This is more likely to occur in
areas where it is difficult to see the material
being cut.

• For operation with the brush blade, do not
cut anything thicker than 1/2 inch or a violent
kickback could occur.

• Do not attempt to touch or stop the blade
when it is rotating.

• A coasting blade can cause injury while it
continues to spin after the engine is stopped
or the throttle trigger is released. Maintain
proper control until the blade has completely
stopped rotating.

• Do not run the unit at high speed when
not cutting.

• If you strike or become entangled with a
foreign object, stop the engine immediately
and check for damage. Have any damage
repaired before attempting further operations.
Do not operate unit with a bent, cracked or
dull blade. Discard blades that are bent,
warped, cracked or broken.

• Do not sharpen the cutting blade. Sharpening
the blade can cause the blade tip to break
off while in use. This can result in severe
personal injury. Replace the blade.

• Stop the engine IMMEDIATELY if you feel
excessive vibration. Vibration is a sign of
trouble. Inspect thoroughly for loose nuts,
bolts or damage before continuing. Repair
or replace affected parts as necessary.

AFTER USE

• Clean cutting blades with a household
cleaner to remove any gum buildup. Oil the
blade with machine oil to prevent rust.

• Lock up and store the cutting blade in an
appropriate area to protect the blade from
unauthorized use or damage.

OTHER SAFETY WARNINGS

• Never store the unit, with fuel in the tank,
inside a building where fumes may reach an
open flame or spark.

• Allow the engine to cool before storing or
transporting. Be sure to secure the unit while
transporting.

• Store the unit in a locked up and dry, or high
and dry place to prevent unauthorized use or
damage. Keep 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 after each use, see
Cleaning and Storage instructions.

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

SAVE THESE INSTRUCTIONS

WARNING: The operation of any power tool can cause foreign objects to be

thrown into your eyes. This can lead to severe eye damage. Before commencing
power tool operation, always wear safety glasses or goggles that are marked as
meeting ANSI Z87.1-1989 standards, and a full face shield when needed.

7

RULES FOR SAFE OPERATION

SAFETY AND 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.

• WARNING - READ OPERATOR'S MANUAL

Failure to follow operating instructions and safety precautions
in the operator's manual can result in serious injury. Read the
operator's manual before starting or operating this unit.

• SAFETY ALERT SYMBOL

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

• PRIMER BULB

Push primer bulb, fully and slowly, 5 to 7 times.

• KEEP BYSTANDERS AWAY

WARNING: Keep all bystanders, especially children and pets,

at least 50 feet (15 m.) from the trimming area.

• INDICATES OIL

Refer to operator's manual for the proper type of oil.

• UNLEADED FUEL

Always use clean, fresh unleaded fuel.

• FOR SERVICE INFORMATION, CALL:

USA: 1-800-345-8746
CANADA: 1-800-265-6778

• WEAR EYE AND HEARING PROTECTION

WARNING: Thrown objects and loud noise can cause severe eye

injury and hearing loss. Wear eye protection meeting ANSI Z87.1­1989 standards and ear protection when operating this unit.

• SHARP BLADE

WARNING: There is a sharp blade on the cutting attachment

shield. To prevent serious injury, do not touch blade.

MEANING

SYMBOL

8

RULES FOR SAFE OPERATION

• THROWN OBJECTS AND ROTATING CUTTER CAN
CAUSE SEVERE INJURY

WARNING: Do not operate without the cutting attachment

shield in place. Keep away from the rotating cutting
attachment.

• ON/OFF STOP CONTROL

ON / START / RUN

• ON/OFF STOP CONTROL

OFF OR STOP

• HOT SURFACE WARNING

Do not touch a hot muffler or cylinder. You may get burned.

These parts get extremely hot from operation. When turned
off they remain hot for a short time.

• TRIMMER/BRUSHCUTTER SAFETY

WARNING: Thrown objects and rotating cutter can cause

severe injury. Keep bystanders, especially children and pets,
at least 50 feet (15 m.) away from the cutting area. The cutting
attachment shield must be used when using the trimmer
cutting attachment.

• BRUSHCUTTERS Replace dull blade.

Do not sharpen the cutting blade. Sharpening the blade can
cause the blade tip to break off while in use. This can result
in severe personal injury.

SYMBOL

MEANING

• CHOKE CONTROL

A • FULL CHOKE position.
B • PARTIAL CHOKE position.
C • RUN position.

On/Off Stop Control

RULES FOR SAFE OPERATION

9

KNOW YOUR UNIT

APPLICATIONS

As a trimmer;

• Cutting grass and light weeds.

• Edging

• Decorative trimming around trees,

fences, etc.

As a brushcutter;

• Cutting weeds and light bush of up to
1/2 inch in diameter.

Other accessories may be used with the
790r. See list of add-ons on page 17.

Handle Hardware

Primer Bulb

Air filter/Muffler Cover

Fuel Cap

Throttle
Control

Power Head

Choke Lever

J-handle

Click-Link
(790r only)

Line Cutting Blade

Cutting Attachment

Shaft Housing

Shaft Grip

Spark Plug

Cutting Attachment Shield

Starter Rope

Support Fitting

Cutting Blade with Cover

ASSEMBLY INSTRUCTIONS

10

INSTALLING AND ADJUSTING THE
J-HANDLE

1. Place the J-handle between the top and
middle clamp pieces (Fig. 1).

(4) Screws

Top Clamp

J-Handle

Middle Clamp

Bottom Clamp

Nuts

2. While holding the three pieces together,
install the four (4) screws through the top
clamp and into middle clamp.

NOTE: The holes in the top and middle clamp

will line up only when assembled
correctly.

3. Place the clamps and j-handle the over the
shaft housing and onto the bottom clamp.

4. Hold each hex nut in the bottom clamp
recess with a finger. Start screws with a large
Phillips screwdriver. Do not tighten until you
make the handle adjustment.

5. Slide the J-handle in or out until the
arrow/white line on the decal touches the
clamp assembly (Fig. 2).

Fig. 1

7. Tighten the clamp screws evenly, until the
J-handle is secure.

6. While holding the unit in the operating
position (Fig. 3), position the J-handle to the
location that provides you the best grip.

Fig. 3

Decal

Fig. 2