MTD CC4125 / CC4175 - Manual (Page 12)

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3. Disconnect the spark plug wire.
4. Clean dirt from around the spark plug. Remove the spark
plug from the cylinder head by turning a 5/8 in. socket
counterclockwise.
5. Remove the engine cover (Fig. 35 & 36).
6. 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. 37). Remove the rocker
arm cover and gasket.
MAINTENANCE AND REPAIR INSTRUCTIONS
Rocker Arm Cover
Fig. 37
Spark Plug Hole
7. 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 looking in the
spark plug hole (Fig. 37)
• Both rocker arms move freely, and both valves are closed
If these statements are not true, repeat this step.
8.
Slide the feeler gauge between the rocker arm and the
valve return spring. Measure the clearance between the
valve stem and rocker arm (Fig. 38). Measure both the
intake and exhaust valves.
Adjusting Nuts
Feeler Gauge
Rocker Arms
Fig. 38
9. If the clearance is not within specification:
a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or
nut driver (Fig. 39).
• To increase clearance, turn the adjusting nut
counterclockwise.
• To decrease clearance, turn the adjusting nut
clockwise.
b. Recheck both clearances, and adjust as necessary.
10. Reinstall the rocker arm cover using a new gasket. Torque
the screw to 20–30 in•lb (2.2–3.4 N•m).
11. Reinstall the engine cover. Check alignment of the cover
before tightening the screws. Tighten screws.
12. Reinstall the muffler cover. Slip the rear tab on the muffler
cover into the engine cover rear slot. Then slide the
remaining slots into the tabs until they snap into place
(Fig. 33).
13. Check the spark plug and reinstall. See Replacing the
Spark Plug.
14. Replace the spark plug wire.
INTAKE
EXHAUST
Fig. 39
Feeler Gauge
Exhaust
Adjusting Nut
Exhaust
Rocker Arm
Exhaust Valve Stem
Intake Valve
Stem
0.003–0.006 in.
(0.076–0.152 mm)
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. Figure 38 and 39 show how to
measure the clearance.