Replacing Spark Plug - Troy-Bilt TB525CS Operator's Manual

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Ifthese statements arenottrue, r epeat thisstep.
7. Slide thefeeler g auge between therocker arm and the
valve return spring. Measure theclearance between the
Rocker Arms INTAKE
Nuts
EXHAUST
Adjusting Nut
.003-.006 in.
(.076-.152 mm) --
Rocker Arm
Feele!Gauge
Feeler Gauge / (_
@
Spark Plug
Hole
Fig. 40
valve stem and rocker arm (Fig. 40). 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 40 and 41.
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. 40).
• 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 Nom).
10. Check the spark plug and reinstall. See Replacing the
Spark Plug.
11. Replace the spark plug wire.
Valve Stem
Fig. 41
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. (0.655 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. 38).
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. 0.025 in.
socket counterclockwise. (0.655 mm.)
4. Replace cracked, fouled or ,L
u
dirty spark plug. Set the air
T
gap at 0.025 in. (0.655 mm.)
using a feeler gauge (Fig. 42).
H
5. Install a correctly-gapped Fig. 42
spark plug in the cylinder head. Turn the 5/8 in. socket
clockwise until snug.
If using a torque wrench torque to:
I
WARNING: Do not sand blast, scrape or clean I
electrodes. Grit in the engine could damage the
I
cylinder.
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