Troy-Bilt Horse TB525CS Operator's Manual page 10

with a Flat-head or
T-25 Torx
screwdriver (Fig. 44).
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. 44).
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. 45). Remove the rocker arm
cover and gasket.
Rocker Arms
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 while
Adjustment Nut
looking in the spark
plug hole (Fig. 45).
• Both rocker arms
move freely, and
both valves are
(.076-0.152 mm)
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. 47). 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. See Figures 46
and 47.
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. 47).
• 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.
REPLACING THE SPARK PLUG
Use a replacement part number 753-05255 spark plug. The correct
air gap is 0.025 in. (0.635 mm.). Remove the plug after every 25
hours of operation and
check its condition.
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 Torx
screwdriver (Fig. 44).
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.
10
MAINTENANCE AND REPAIR INSTRUCTIONS
Cache-
culbuteur
Trou de
bougie
Fig. 45
Intake
Feeler Gauge
Fig. 46
Rocker Arm
.003-.006 in.
Fig. 47
0.025 in.
(0.635 mm.)
Fig. 48
4. Replace cracked, fouled or dirty spark plug. Set the air gap at
0.025 in. (0.635 mm.) using a feeler gauge (Fig. 48).
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.
WARNING:
electrodes. Grit in the engine could damage the
cylinder.
SPARK ARRESTOR MAINTENANCE
1. Remove the rear engine cover. See Rocker Arm Clearance.
2. With a flat blade screwdriver or Torx T-20 bit and a T-25 bit,
remove the screws attaching the spark arrestor cover to the
muffler (Fig. 49).
Adjustment
Nuts
3. Pull the tab on the
spark arrestor cover
out of the muffler.
Exhaust
Remove the spark
arrestor cover.
4. Remove the spark
arrestor screen from
the spark arrestor
cover.
Feeler
Gauge 5. Clean the spark
arrestor screen with a wire brush or replace it.
6. Reinstall the spark arrestor screen, spark arrestor cover and screws.
WARNING:
Valve Stem
turn your unit off and allow it to cool before you clean
or service it.
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 60 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.
NOTE: Remove the spark plug and drain all of the oil from the
cylinder before attempting to start the trimmer after
storage.
4. Change the oil, referring to Changing the Oil. Dispose of the
old oil in accordance to Federal, State and Local regulations.
5. Thoroughly clean the unit and inspect for any loose or
damaged parts. Repair or replace damaged parts and tighten
loose screws, nuts or bolts. The unit is ready for storage.
TRANSPORTING
• Allow the engine to cool before transporting.
• Secure the unit while transporting.
• Drain the gas tank before transporting.
• Tighten gas cap before transporting.
Do not sand blast, scrape or clean
Spark Arrestor Screen
Muffler
Diverter
Slot
Fig. 49
To avoid serious personal injury, always
T-20 Screw
T-25 Screw