MTD CC4105 User Manual

Page 13

Disconnect the spark plug wire.

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

Remove the engine cover (Fig. 35 & 36).

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

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.

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.

Adjusting Nuts

Feeler Gauge

Rocker Arms

Fig. 38

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)