Troy-Bilt TB516 Operation Manual Download Page 4

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REPLACING THE SPARK PLUG

Use a replacement

Champion® #RDZ4H

spark plug. The correct air gap is

0.025 in. (0.635 mm)

. Remove the plug

and check its condition per the maintenance schedule.

1. Stop the engine and allow it to cool. Remove the six (6) screws on the back of the engine cover with a Flat-head or

T-25 screwdriver (Fig. 20).

2. Grasp the plug wire firmly and pull the cap from the spark plug.

3. Clean dirt from around the spark plug. Remove the spark plug from the cylinder head by turning a 5/8 in. socket

counterclockwise.

4. Replace cracked, fouled or dirty spark plug. Set the air gap at

0.025 in. (0.635

mm)

using a feeler gauge (Fig. 24).

5. Install a correctly-gapped spark plug in the cylinder head. Turn the 5/8 in. socket

clockwise until snug.

If using a torque wrench torque to:

110-120 in.•lb. (12.3-13.5 N•m)

Do not over-tighten.

PROBLEM

SOLUTION

IDLE SPEED ADJUSTMENT

The idle speed of the engine is adjustable. An idle adjustment screw is between the
air filter cover and the engine starter housing (Fig. 19).

NOTE:

Careless adjustments can seriously damage your unit. An authorized
service dealer should make carburetor adjustments.

If, after checking the fuel and cleaning the air filter, the engine still will not idle, adjust the idle speed screw as follows:

1. Start the engine and let it run at a high idle for a minute to warm up. Refer to

Starting and Stopping Instructions

2. Release the throttle lever and let the engine idle. If the engine stops, insert a small Phillips in between the air filter

cover and the engine cover (Fig. 19). Turn the idle speed screw in, clockwise, 1/8 of a turn at a time (as needed)
until the engine idles smoothly.

NOTE:

The blade should not rotate when the engine idles.

3. If the blade rotates when the engine idles, turn the idle speed screw counterclockwise 1/8 of a turn at a time (as

needed), to reduce idle speed.

Checking the fuel, cleaning the air filter, and adjusting the idle speed should solve most engine problems. If not and all
of the following are true:

• the engine will not idle

• the engine hesitates or stalls on acceleration

• there is a loss of engine power

Have the carburetor adjusted by an authorized service dealer.

ROCKER ARM CLEARANCE

This requires disassembly of the engine. If unsure or unqualified to perform this, take the unit to an authorized service center.

NOTE:

Inspect the valve to rocker arm clearance with a feeler gauge per the
maintenance schedule.

• The engine must be cold when checking or adjusting the valve clearance.

• This task should be performed inside, in a clean, dust free area.

1. Remove the six (6) screws on the back of the engine cover with a Flat-head or T-

25 Torx screwdriver (Fig. 20).

2. Disconnect the spark plug wire.

3. Clean dirt from around the spark plug. Remove the spark plug from the cylinder

head by turning a 5/8 in. socket counterclockwise.

4. Remove the engine cover (Fig. 20).

5. Clean dirt from around the rocker arm cover. Remove the screw holding the rocker

arm cover with a large flat blade screwdriver or Torx T-25 bit (Fig. 21). Remove the
rocker arm cover and gasket.

6. Pull the starter rope slowly to bring the piston to the top of its travel, (known as

top dead center). Check that:

•

The piston is at the top of its travel. This should be done by looking into the
spark plug hole. (Fig. 21)

•

Both rocker arms move freely, and both valves are closed

If these statements are not true, repeat this step.

7. Slide the feeler gauge between the rocker arm and the valve return spring.

Measure the clearance between the valve stem and rocker arm (Fig. 23). Measure
both the intake and exhaust valves.

The recommended clearance for both intake and exhaust is

.003 – .006 in. (.076 –

0.152 mm)

. Use a standard automotive .005 in. (0.127 mm) feeler gauge. The feeler

gauge should slide between the rocker arm and valve stem with a slight amount of
resistance, without binding (Fig. 23).

8. If the clearance is not within specification:

a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or nut driver (Fig. 23).

•

To increase clearance, turn the adjusting nut counterclockwise.

•

To decrease clearance, turn the adjusting nut clockwise.

b. Recheck both clearances, and adjust as necessary.

9. Reinstall the rocker arm cover using a new gasket. Torque the screw to

20–30

in•lb (2.2–3.4 N•m)

10. Check the spark plug and reinstall. See

Replacing the Spark Plug

11. Replace the spark plug wire.

12. Reinstall the engine cover. Check alignment of the cover before tightening the

screws. Tighten screws.

UNIT*

Engine Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Air-Cooled, 4-Cycle

Displacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 cc

Operating RPM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6,800+ rpm

Idle Speed RPM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,800 - 4,200 rpm

Valve clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.003–0.006 in. (0.076–0.152 mm)

Spark Plug Gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.025 in. (0.635 mm)

Lubrication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAE 30 Oil

Crankcase Oil Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.04 oz (90 ml)

Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unleaded

Fuel Tank Capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 oz (414 ml)

Unit Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.7 lbs. (11.2 kg)

Cutting Depth (maximum) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.75 in. (44.5 mm)

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.

ELECTRIC STARTER AND POWER START BIT™ FEATURES

This unit can be started with an optional Electric Starter or Power Start Bit™ (Items Sold Separately!). If choosing to
start the unit using one of these features or have questions, please contact your local retailer or call

1-800-828-5500

the U.S. (

1-800-668-1238

in Canada) for more information and purchasing. You may also go to

www.troybilt.com

www.troybilt.ca

Electric Start

Feature

WARNING:

Do not sand blast, scrape or clean spark plug

electrodes. Grit in the engine could damage the cylinder.

Fig. 19

Idle Adjustment Screw

Fig. 20

Fig. 21

Screws

Fig. 22

MAINTENANCE AND REPAIR INSTRUCTIONS

Fig. 23

WARNING:

The blade may spin during idle speed adjustments.

Wear protective clothing and observe all safety instructions to prevent
serious personal injury.

Fig. 24

0.025 in.

(0.635 mm)

Screws

View of the Rear

Engine Cover

Screw

Rocker

Arm Cover

Spark

Plug Hole

Adjusting

Nuts

INTAKE

EXHAUST

Rocker

Arms

0.003–0.006 in.

(0.076–0.152 mm)

Feeler
Gauge

Exhaust

Adjusting Nut

Rocker Arm

Valve Stem

OPTIONAL ACCESSORY

Old fuel

Drain gas tank and add fresh fuel

Fouled spark plug

Replace or clean the spark plug

Old fuel

Drain gas tank and add fresh fuel

Blade bound with dirt or grass

Stop the engine and clean the blade

Dirty air filter

Clean or replace the air filter

Empty fuel tank

Fill fuel tank with fuel

Primer bulb was not pressed enough

Press the primer bulb 10 times or until fuel is visible

Old fuel (over 30 days)

Drain fuel tank and add fresh fuel

Fouled spark plug

Replace or clean the spark plug

Cold weather start lever is in closed position

Move cold weather start lever to open position

Air filter is plugged

Replace or clean the air filter

Old fuel

Drain gas tank and add fresh fuel

Improper idle speed

Adjust according to the

Idle Speed Adjustment

section

TROUBLESHOOTING

THE ENGINE WILL NOT START

THE ENGINE WILL NOT IDLE

THE ENGINE WILL NOT ACCELERATE

NOTE:

For repairs beyond the minor adjustments listed above, locate your nearest authorized service center by
calling the Customer Support Department at

1-800-828-5500

(U.S.) or

1-800-668-1238

(Canada).

THE ENGINE LACKS POWER OR STALLS

BLADE REPLACEMENT

1. Place the 5/16” Allen wrench in the spindle

hole (Fig. 11).

2. While holding the Allen wrench in place, loosen

the nut with a 15/16” wrench by turning it
counterclockwise (Fig. 11).

3. Re move the nut and blade. Keep the nut for

new blade installation.

4. Install the new blade and nut (Fig. 12).

NOTE:

Make sure the blade edges are facing the proper direction (Fig. 12). The unit will not function correctly if the
edger blade is installed backward.

5. While holding the Allen wrench in the spindle hole, tighten the nut by turning the wrench clockwise until tight (Fig. 11).

NOTE:

Make sure that the blade stays flat and centered against the output shaft throughout installation.

CHECKING THE OIL LEVEL

The importance of checking and maintaining the
proper oil level in the crankcase cannot be
overemphasized. Check oil before each use:

1. Stop the engine and allow oil to drain into the

crankcase.

2. Place unit on a flat, level surface.

3. Keep dirt, grass clippings and other debris out

of the engine. Clean the area around the
dipstick before removing it.

4. Remove the oil fill plug.

5. Look into the oil fill hole, use a flashlight if needed. The oil should be just touching the inner most thread (Fig. 13).

6. If the oil level is not touching the inner most thread on the oil fill hole, add a small amount of oil to the oil fill hole

and recheck (Fig. 16). Repeat this procedure until the oil level reaches the inner most thread on the oil fill hole.

NOTE:

Do not overfill the unit.

NOTE:

Make sure the O-ring is in place on the oil fill plug when checking and changing the oil (Fig. 14).

CHANGING THE OIL

Change the oil per the maintenance schedule.
Change the oil while the engine is still warm. The
oil will flow freely and carry away more impurities.

1. Remove the oil fill plug.

2. Pour the oil out of the oil fill hole and into a

container by tipping the unit to a vertical
position (Fig. 15). Allow ample time for
complete drainage.

3. Wipe up any oil residue on the unit and clean

up any oil that may have spilled. Dispose of
the oil according to federal, state and local regulations.

4. Refill the crankcase with 3.04 fl.oz. (90 ml) of SAE 30 SF, SG, SH oil.

NOTE:

Use the bottle and spout saved from initial use to measure the correct
amount of oil. The top of the label on the bottle measures approximately
3.04 fl.oz. (90 ml) (Fig. 17). Check the level, See

Checking the Oil Level

. If the

level is low, add a small amount of oil and recheck. Do not overfill (Fig. 13).

5. Replace the oil fill plug.

AIR FILTER MAINTENANCE

Cleaning the Air Filter

Clean and re-oil the air filter per the maintenance schedule. It is an important item to
maintain. Failure to maintain the air filter properly can result in poor performance or
can cause permanent damage to the engine.

1. Open the air filter cover. Unscrew the knob on the left side of the cover. Swing the

cover out (Fig. 18).

2. Remove the air filter (Fig. 18).

3. Wash the filter in detergent and water. Rinse the filter thoroughly and allow it to

dry.

4. Apply enough clean SAE 30 motor oil to lightly coat the filter.

5. Squeeze the filter to spread and remove excess oil.

6. Replace the filter (Fig. 18).

NOTE:

Operating the unit without the air filter, will

VOID

the warranty.

7. Make sure the back plate is correctly positioned (Fig. 18).

8. Swing the air filter cover closed and tighten the knob (Fig. 18).

Fig. 11

Fig. 12

Edger Blade

Nut

Fig. 13

Oil Max Fill Line

Fig. 15

Fig. 17

Fig. 18

Air Filter

Tighten

Loosen

Spindle

Hole

Oil Fill Plug

Fig. 14

O-Ring

Oil Fill Hole

Air Filter

Cover

Knob

Back Plate

Hooks

Fill Level

Fig. 16

Oil Fill

Hole

CLEANING

Use a small brush to clean off the outside of the unit. Do not use strong detergents. Household cleaners that contain
aromatic oils such as pine and lemon, and solvents such as kerosene, can damage plastic housing or handle. Wipe off
any moisture with a soft cloth.

STORAGE

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

• Allow the engine to cool before storing.

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

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

• Store the unit out of the reach of children.

LONG TERM STORAGE

1. Drain all gasoline from the gas tank into a container. Do not use gas that has been stored for more than 30 days.

Dispose of the old gasoline in accordance to federal, state and local regulations.

2. Start the engine and allow it to run until it stalls. This ensures that all gasoline has been drained from the carburetor.

3. Allow the engine to cool. Remove the spark plug and put 5 drops of high quality motor oil into the cylinder. Pull the

starter rope slowly to distribute the oil. Reinstall the spark plug.