Know Your Unit; Assembly Instructions; Oil And Fuel Information; Starting/Stopping Instructions - Troy-Bilt TB21 EC Manual Del Operador

KNOW YOUR UNIT

APPLICATIONS
As a trimmer:
• Cutting grass and light weeds.
• Edging
• Decorative trimming around trees,
fences, etc.
On/Off Control
EZ-Link™
Shaft Housing
Line Cutting
Blade
Cutting Head Shield
Cutting Head

ASSEMBLY INSTRUCTIONS

INSTALL CUTTING ATTACHMENT SHIELD
WARNING:
To prevent serious personal injury, never operate the trimmer without the cutting
attachment shield in place.
Use the following instructions if the cutting attachment shield on the unit is not installed. Use only the instructions that
apply to the type of shaft and shield that the unit is equipped with.
1. Place the cutting attachment shield onto the shaft
housing. Be sure the guard mounting bracket slides
into the slot on the edge of the cutting shield. Rotate
the shield into place, counterclockwise (Fig. 1). The
holes in the guard mounting bracket and cutting
attachment shield will line up.
2. From inside the cutting attachment shield, push
the square bolt through the hole until the
threaded end protrudes through the guard
mounting bracket (Fig. 2).
3. Put the washer on the bolt, then screw the wing nut onto the bolt and tighten.
INSTALL AND ADJUST THE D-HANDLE
1. Push the D-handle down onto the shaft housing (Fig. 3). The hex bolt hole in the
handle should be on the left side.
2. Insert the the bolt into the hex hole in the handle and push through. Place the
washer on the bolt, then screw the wing nut onto the bolt. Do not tighten until
making the handle adjustment.
3. Rotate the D-handle to place the grip above the top of the shaft housing. Place it
a minimum of 6 inches (15.24 cm) from the end of the shaft grip.
4. While holding the unit in the operating position (Fig. 10), move the D-handle to the location that provides the best grip.
5. Tighten the wing nut until the D-handle is secure.
OPERATING THE EZ-LINK™ SYSTEM
The EZ-Link™ system enables the use of these optional Add-Ons.
Mach 4® Trimmer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AF720
Hedge Trimmer*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AH720*
Brushcutter* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BC720*
Bladed Pruner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BP720
Blower Trimmer* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BT720*
Blower Vacuum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BV720
Cultivator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GC720
Lawn Dethatcher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LD720
Edger*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LE720*
Pole Saw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PS720
Straight Shaft Trimmer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SS725
Snow Thrower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ST720
Turbo Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TB720
* Do NOT use this Add-On with an electric powered unit.
REMOVING THE ADD-ON
1. Turn the knob counterclockwise to loosen (Fig. 6).
2. Press and hold the release button (Fig. 4).
3. While firmly holding the upper shaft housing,
pull the lower shaft housing straight out of the
EZ-Link™ coupler (Fig. 5).
INSTALLING THE ADD-ON
NOTE: To make installing or removing the add-
on easier, place the unit on the ground
or on a work bench.
1. Turn knob counterclockwise to loosen (Fig. 6).
2. While firmly holding the add-on, push it straight into the EZ-Link™ coupler (Fig. 5).
NOTE: Aligning the release button with the guide recess will help installation (Fig. 4).
3. Turn the knob clockwise to tighten (Fig. 6).
For decorative trimming/edging with the line cutting head, lock the release button
into the 90° hole (Fig. 6).

OIL AND FUEL INFORMATION

OIL AND FUEL MIXING INSTRUCTIONS
Old and/or improperly mixed fuel are the main reasons for the unit not running properly. Be sure to use fresh, clean
unleaded fuel. Follow the instructions carefully for the proper fuel/oil mixture.
DEFINITION OF BLENDED FUELS
WARNING:
It has been proven that fuel containing greater than 15% ethanol will likely damage this engine
and void the warranty.
Today's fuels are often a blend of gasoline and oxygenates such as ethanol, methanol, or MTBE (ether). Alcohol-
blended fuel absorbs water. As little as 1% water in the fuel can make fuel and oil separate. It forms acids when
stored. When using alcohol-blended fuel, use fresh fuel (less than 60 days old).
USING BLENDED FUELS
If choosing to use a blended fuel, or its use is unavoidable, follow recommended precautions:
• Always use the fresh fuel mix explained in the operator's manual
• Always agitate the fuel mix before fueling the unit
Spark Plug
Muffler
Starter Rope Grip
Choke Lever
Fuel Cap
Air Filter Cover
Shaft Grip
Throttle Control
D-Handle
Cutting Mount
Shield Bracket
Square Bolt
Fig. 1
Shaft Grip
Minimum
6 inches
(15.24 cm)
Bolt
EZ-Link™ Coupler Primary Hole
Release
Button
Upper Shaft
Housing
Guide Recess
Fig. 4 Fig. 5
90˚ Edging Hole
(Trimmer Only)
• Drain the tank and run the engine dry before storing the unit
USING FUEL ADDITIVES
CAUTION:
reliability, pay strict attention to the oil and fuel mixing instructions
on the 2-cycle oil container. Using improperly mixed fuel can
severely damage the engine.
The bottle of 2-cycle oil contains a fuel additive which will help inhibit corrosion and
minimize the formation of gum deposits. It is recommended to use our 2-cycle oil
with this unit.
If unavailable, use a good 2-cycle oil designed for air-cooled engines along with
a fuel additive, such as STA-BIL® Gas Stabilizer or an equivalent. Add 0.8 oz.
(23 ml.) of fuel additive per gallon of fuel according to the instructions on the container. NEVER add fuel additives directly
to the unit's fuel tank.
Thoroughly mix the proper ratio of 2-cycle engine oil with unleaded fuel in a separate fuel can. Use a 40:1 fuel/oil ratio.
Do not mix them directly in the engine fuel tank. See the table for specific gas and oil mixing ratios.
NOTE: One gallon (3.8 liters) of unleaded fuel mixed with one 3.2 oz. (95 ml.) bottle of 2-cycle oil makes a 40:1 fuel/oil ratio.
NOTE: Dispose of the old fuel/oil mix in accordance to Federal, State and Local regulations.
WARNING:
and allow it to cool before filling the fuel tank. Do not smoke while filling the tank. Keep sparks and open
flames at a distance from the area.
FUELING THE UNIT
Primer Bulb
WARNING:
fuel cap securely in place.
WARNING:
Avoid creating a source of ignition for spilled fuel. Do not start the engine until fuel vapors dissipate.
1. Turn unit on its side, with the fuel cap facing up, and remove the fuel cap.
2. Place the gas container's spout into the fill hole on the fuel tank and fill the tank.
NOTE: Do not overfill the tank.
3. Wipe up any gasoline that may have spilled.
4. Reinstall the fuel cap.
5. Move the unit at least 30 ft. (9.1 m) from the fueling source and site before starting the engine.
WARNING:
Carbon monoxide exhaust fumes can be lethal in a confined area.
WARNING:
starting position when pulling the starter rope (Fig. 9). To avoid serious
injury, the operator and unit must be in a stable position while starting.
STARTING INSTRUCTIONS
1. Mix fuel with oil. Fill fuel tank with fuel/oil mixture. See Oil and Fuel Mixing
Instructions.
2. Fill the fuel tank with fresh, clean fuel mix. Refer to Fueling the Unit.
NOTE: There is no need to turn the unit on. The On/Off Control is in the ON ( I )
position at all times (Fig. 7).
3. Fully press and release the primer bulb 10 times, slowly. Some amount of fuel
should be visible in the primer bulb and fuel lines (Fig. 8). If fuel can not be seen in
the bulb, press and release the bulb until fuel is visible.
4. Place the choke lever in Position 1 (Fig. 8).
5. Crouch in the starting position (Fig. 9). Squeeze the throttle control lever. Pull the
starter rope 5 times.
6. Place the choke lever in Position 2 (Fig. 8)
Washer
7. Squeeze the throttle control, pull the starter rope in a controlled motion 3 to 5
times to start engine.
8. Keep the throttle squeezed and allow the engine to warm up for 30 to 60 seconds.
9. Continue squeezing the throttle control, move the choke lever to Position 3 (Fig. 8)
and continue warming the engine for an additional 60 seconds. The unit may be
Wing
Nut
used during this time.
NOTE: Unit is properly warmed up when engine accelerates without hesitation.
Fig. 2
IF... the engine hesitates, return the choke lever to Position 2 (Fig. 8) and continue warm-up.
Shaft D-Handle
IF... the engine does not start, go back to step 3.
Housing
IF... the engine fails to start after a few attempts, place the choke lever in Position 3 and squeeze the throttle
control. Pull the starter rope out with a controlled and steady motion 3 to 8 times. The engine should start. If
Tighten
not, repeat.
Wing
IF WARM... If the engine is already warm, start the unit with the choke lever in Position 2. After the unit starts, move
Nut
the choke lever to Position 3.
Washer
IF USING THE OPTIONAL ELECTRIC STARTER OR POWER START BIT™ ACCESSORY
Fig. 3
HOW TO START THE UNIT USING THE ELECTRIC STARTER OR POWER START BIT ACCESSORY.
NOTE- This Unit Can Use an Electric Start or Power Start Bit™ Optional Accessory!
Please refer to the Electric Starter or Power Start Bit operator's manual for proper use of this feature. (Items
Sold Separately! Please refer to page 5 of this manual about purchasing these accessories.)
STARTING INSTRUCTIONS
1. Mix fuel with oil. Fill fuel tank with fuel/oil mixture. See Oil and Fuel Mixing Instructions.
2. Fill the fuel tank with fresh, clean fuel mix. Refer to Fueling the Unit.
NOTE: There is no need to turn the unit on. The On/Off Control is in the ON ( I ) position at all times (Fig. 7).
3. Fully press and release the primer bulb 10 times, slowly. Some amount of fuel should be visible in the primer bulb
(Fig. 9). If fuel cannot be seen in the bulb, press and release the bulb until fuel is visible.
4. Move the choke lever to Position 1 (Fig. 8).
5. Crouch in the starting position (Fig. 9). Place the electric starter or power start bit into the back of the unit. Refer to
the Operation section of the Electric Starter or Power Start Bit operator's manual.
6. Squeeze the throttle control lever. Press and hold the electric starter or drill ON (I) button for 2 seconds.
7. Move the choke lever to Position 2 (Fig. 8).
8. Squeeze the throttle control lever, press and hold the electric starter or drill ON (I) button for 2-second intervals until
the unit starts.
9. Continue to squeeze the throttle control, remove the electric starter or drill from the unit and allow the engine to
warm up for 30 to 60 seconds.
10. Continue squeezing the throttle control, move the choke lever to Position 3 (Fig. 8) and run the unit for an
additional 60 seconds. The unit may be used during this time.
NOTE: Unit is properly warmed up when engine accelerates without hesitation.
IF... the engine hesitates, return the choke lever to Position 2 (Fig. 8) and continue warm-up.
IF... the engine does not start, go back to step 3.
IF... the engine fails to start after a few attempts, place the choke lever in Position 3 and squeeze the throttle
control. Press and hold the electric starter or drill ON (I) button for 2-second intervals until the unit starts.
IF WARM... If the engine is already warm, start the unit with the blue choker lever in Position 2. After the unit starts,
Lower Shaft
Housing
move the blue choker lever to Position 3.
STOPPING INSTRUCTIONS
1. Release the throttle control and allow the engine to cool down by idling.
2. Press and hold the On/Off Control switch in the OFF (O) position until the unit comes to a complete stop (Fig. 7).
HOLDING THE UNIT
Knob
WARNING: Always wear eye, hearing, foot and body protection to reduce the risk of injury when operating
this unit.
Fig. 6
Before operating the unit, stand in the operating position (Fig. 10). Check for the
following:
• The operator is wearing eye protection and proper clothing
• With a slightly-bent right arm, the operator's hand is holding the shaft grip
• The operator's left arm is straight, the left hand holding the D-handle
• The unit is at waist level
• The cutting head is parallel to the ground and easily contacts the grass without
the need to bend over
ADJUSTING TRIMMING LINE LENGTH
WARNING:
premature engine failure and / or unit damage.
The Bump Head™ cutting head allows the release of trimming line without stopping the engine. To release more line,
lightly tap the cutting head on the ground (Fig. 11) while operating the unit at high speed.
NOTE: Always keep the trimming line fully extended. Line release becomes more difficult when the cutting line gets shorter.
OIL AND FUEL INFORMATION
For proper engine operation and maximum
Gasoline is extremely flammable. Ignited vapors may explode. Always stop the engine
Remove fuel cap slowly to avoid injury from fuel spray. Never operate the unit without the
Add fuel in a clean, level and well ventilated outdoor area. Wipe up any spilled fuel immediately.

STARTING/STOPPING INSTRUCTIONS

Operate this unit in a well-ventilated outdoor area.
Avoid accidental starting. Make sure you are in the

OPERATING INSTRUCTIONS

Do not remove or alter the line cutting blade assembly. Excessive line length will cause
UNLEADED GAS 2 CYCLE OIL
1 GALLON US 3.2 FL. OZ.
(3.8 LITERS) (95 ml)
1 LITER 25 ml
MIXING RATIO - 40:1
OFF (O)
ON (I)
Throttle
Control
Fig. 7
Choke Lever Primer Bulb
Fig. 8
Starting Position
Starter
Rope
Fig. 9
Fig. 10
3