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OPERATING INSTRUCTIONS

17

MAINTENANCE AND REPAIR INSTRUCTIONS

WARNING: 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.

Cutting Blade Operating Tips:

To establish a rhythmic cutting procedure:
• Plant feet firmly, comfortably apart.

• Bring the engine to full throttle before

entering the material to be cut. The blade
has maximum cutting power at full throttle
and is less likely to bind, stall, or cause 
blade thrust, which can result in serious
personal injury to the operator or others.

• Cut while swinging the upper part of your

body from right to left.

• Always release the throttle trigger and allow

the engine to return to idle speed when not
cutting. Swing the unit in the same direction
as the blade spins, which increases the
cutting action.

• Move forward to the next area to be cut after

the return swing and plant feet again.

• The brush blade is designed with a second

set of teeth, which can be used by removing
the blade, turning it upside down, and
reinstalling it.

To reduce the chance of material wrapping
around the blade, follow these steps:

• Cut at full throttle.

• Swing the unit into material to be cut from

your right to your left (Fig. 27).

• Avoid the material just cut as you make the

return swing.

Fig. 27

MAINTENANCE SCHEDULE

These required maintenance procedures should
be performed at the frequency stated in the
table. They should also be included as part of
any seasonal tune-up.

For a new engine, change the oil after the first

10 hours

of operation. See 

Changing the Oil

(Pg. 22).

WARNING:

To prevent serious

personal injury, never perform any
type of maintenance or repairs with
the unit running or while it is hot.
Allow the unit to cool down.
Disconnect spark plug wire to 
make sure the unit will not start.

FREQUENCY

MAINTENANCE REQUIRED

REFER TO:

Daily or Before

Check oil level.

Page 21

Starting Engine

Fill fuel tank with correct type of fuel.

Page 13

Every 10 Hours

Clean and re-oil air filter.

Page 20

Every 25 Hours

Change oil.

Page 22

Every 50 Hours

Check spark plug condition and gap.

Page 23

Every 50 Hours

Check rocker arm to valve clearance 

Page 22

and adjust as required

Summary of Contents for 1090r

Page 1: ...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 4 Cycle Gas Trimmer Brushcutter 1090r...

Page 2: ...Instructions 15 17 A Operating Click Link System 15 B Adjusting Trimming Line Length 16 C Decorative Trimming 16 D Edging 16 E Using the Cutting Blade 16 VII Maintenance and Repair Instructions 17 23...

Page 3: ...a Maine Oregon and Washington All U S Forest Land and the state of California Public Resources Codes 4442 and 4443 Oregon and Washington require by law that certain internal combustion engines operate...

Page 4: ...ry 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 READ ALL INSTRUCTIONS BEFORE OPERATING...

Page 5: ...g 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 WHILE OPERATING WITH CUTT...

Page 6: ...owly 5 to 7 times KEEP BYSTANDERS AWAY WARNING Keep all bystanders especially children and pets at least 50 feet 15 m away from the trimming area UNLEADED FUEL Always use clean fresh unleaded fuel AFT...

Page 7: ...CONTROL A START position B RUN position INDICATES OIL Refer to operator s manual for the proper type of oil SHARP BLADE WARNING Sharp blade on string guard To prevent serious injury do not touch line...

Page 8: ...s and weeds Also for decorative trimming around trees fences etc Use the 4 tooth brush blade for weeds and light brush of up to 1 2 inch in diameter Other attachments may be used with this unit See th...

Page 9: ...he unit in the operating position Fig 2 adjust rotate the handle forward and back to a position that provides you the best grip 4 Tighten the mounting screws Fig 1 Fig 3 Fig 2 INSTALLING THE HARNESS W...

Page 10: ...unt by removing the three 3 screws with a flat blade screwdriver Fig 6 Store parts for future use 4 Remove the nut blade retainer and blade Store the nut and blade together for future use in a secure...

Page 11: ...s hot with use and can result in injury to the operator When the unit is turned off it remains hot for a short time Do not touch the gear housing until it has cooled 1 Align the shaft bushing hole wit...

Page 12: ...e unit do not start or operate this unit with the locking rod in the locking rod slot 10 Remove the cutting blade cover by un snapping the plastic lock on the cover and pulling it from the blade Store...

Page 13: ...before storing the unit USE OF FUEL ADDITIVES The use of fuel additive such as STA BIL Gas Stabilizer or an equivalent will inhibit corrosion and minimize the formation of gum deposits Add 0 8 oz 23 m...

Page 14: ...nit in the starting position squeeze the throttle control and pull the starter rope briskly until the engine sounds like it wants to run normally 2 to 5 pulls Fig 20 7 Place the choke lever in the RUN...

Page 15: ...nts to be installed on the unit The optional attachments are Blower Vacuum BV720r Cultivator GC720r Edger LE720r Hedge Trimmer HS720r Snow Thrower ST720r Straight Shaft Trimmer SS725r Sweeper Blower S...

Page 16: ...g all vegetation around trees posts fences etc Rotate the entire unit so that the cutting head is at a 30 angle to the ground Fig 25 ADJUSTING TRIMMING LINE LENGTH Your unit is equipped with a string...

Page 17: ...ext area to be cut after the return swing and plant feet again The brush blade is designed with a second set of teeth which can be used by removing the blade turning it upside down and reinstalling it...

Page 18: ...u use a larger line Removing the Existing Reel 1 Hold the outer spool with one hand and unscrew the Bump Knob clockwise Fig 28 Inspect the captured bolt inside the Bump Knob to make sure it moves free...

Page 19: ...3 Reinstalling the Reel 1 Insert the ends of the line through the eyelets in the outer spool and place inner reel inside the outer spool Fig 34 Then grasp the ends and pull firmly to release the line...

Page 20: ...out and up Fig 35 3 Remove the air filter Fig 35 Fig 37 Fig 38 Fig 39 5 Apply enough clean SAE 30 motor oil to lightly coat the filter Fig 37 6 Squeeze the filter to spread and remove excess oil Fig...

Page 21: ...ise 1 2 turn until the engine stabilizes Fig 40 4 If the cutting head keeps rotating after the trigger is released turn the idle speed screw counterclockwise 1 2 turn until the head stops rotating Fig...

Page 22: ...te and local regulations 4 Refill the crankcase with 3 4 fluid oz 100 ml of SAE 30 SF SG SH oil Use the bottle and spout from initial use 5 Reinstall the oil fill plug dipstick NOTE Make sure the O ri...

Page 23: ...in lb 11 3 12 3 N m Reinstall the spark plug wire 3 Disconnect the spark plug wire 4 Remove the spark plug and then remove the engine cover 5 Remove the rocker arm cover and gasket Fig 46 6 While look...

Page 24: ...nsures that all fuel has been drained from the carburetor 3 Allow the engine to cool Remove the spark plug and put approximately 1 oz 30 ml of any high quality motor oil or 4 cycle oil into the cylind...

Page 25: ...tarting procedure WITHOUT choke lever in the START position Drain fuel tank Add fresh fuel Replace or clean spark plug Replace or clean air filter Drain fuel tank Add fresh fuel Drain fuel tank Add fr...

Page 26: ...e Diameter 0 095 inches 2 41 mm Cutting Path Diameter 18 inches 44 0 cm Gear Box Ratio 1 23 1 ENGINE Engine Type Air Cooled 4 Cycle Displacement 1 6 cu in 26 2 cc Clutch Type Centrifugal Operating RPM...

Page 27: ...he engine or equipment is delivered to the retail purchaser The manufacturer warrants to the initial owner and each subsequent purchaser that the engine is free from defects in material and workmanshi...

Page 28: ...tion this warranty does not cover A Tune ups Spark Plugs Carburetor Adjustments Filters B Wear items Bump Knobs Outer Spools Cutting Line Inner Reels Starter Pulley Starter Ropes Drive Belts RYOBI res...

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