![background image](http://html.mh-extra.com/html/troy-bilt/4-cycle/4-cycle_operators-manual_1173361016.webp)
16
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.
NOTE: To ease engine cover removal, pull the starter
rope out a little to give some slack.
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. 26). Remove the rocker arm cover and gasket.
Rocker Arm Cover
Fig. 26
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. 26).
• Both rocker arms move freely, 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. 27 & 28).
Measure both the intake and exhaust valves.
Adjusting Nuts
Feeler Gauge
Rocker Arms
Fig. 27
Fig. 28
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. 28).
• 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. Check the spark plug and reinstall. See Replacing
the Spark Plug.
13. Replace the spark plug wire.
INTAKE
EXHAUST
MAINTENANCE AND REPAIR INSTRUCTIONS
The recommended clearance for the intake is .003 – .006
in. (.076 – 0.152 mm). The recommended clearance for
the exhaust is .013 – .016 in. (.330 – 0.406 mm).
Use a standard automotive feeler gauge at .005 and .015 in.
(0.127 and 0.381 mm). The feeler gauge should slide
between the rocker arm and valve stem with a slight amount
of resistance, without binding. Figure 27 shows how to
measure the intake clearance, while Figure 28 shows the
exhaust clearance.
Feeler Gauge
Exhaust
Adjusting Nut
Exhaust
Rocker Arm
Exhaust
Clearance:
.013–.016 in.
(.330–0.406 mm)
Exhaust Valve Stem
Intake Valve
Stem
Intake Clearance:
.003–.006 in.
(.076–0.152 mm)
Summary of Contents for 4-Cycle
Page 1: ...P N 769 00874 10 03 PRINTED IN USA ...
Page 10: ...10 STARTING STOPPING INSTRUCTIONS Starter Rope Throttle Control ON I OFF O ...
Page 13: ...13 MAINTENANCE AND REPAIR INSTRUCTIONS ...
Page 23: ...P N 769 00874 10 03 IMPRIMÉ AUX ÉTATS UNIS ...
Page 32: ...F10 INSTRUCTIONS DE DÉMARRAGE ET ARRÊT ...
Page 43: ...F21 REMARQUES ...
Page 44: ...F22 REMARQUES ...
Page 47: ...P N 769 00874 10 03 IMPRESO EN LOS EE UU ...
Page 54: ...E8 INFORMACION DEL ACEITE Y DEL COMBUSTIBLE Fig 7 Fig 8 ...
Page 67: ...E21 NOTAS ...
Page 69: ...E23 PARTS LIST ENGINE PARTS MODEL TB144 4 CYCLE GAS CULTIVATOR ...
Page 71: ...E25 PARTS LIST ...