Troy-Bilt TB26TB - Manual (Page 11)

11
3. Remove the screw behind
the engine cover (Fig. 36).
4. Disconnect the spark plug
wire.
5. Clean dirt from around the
spark plug. Remove the
spark plug from the cylinder
head by turning a 5/8 in.
socket counterclockwise.
6. Remove the engine cover.
7. 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.
8. 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.
9. 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. See Figures 38 and 39.
10. 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.
Screw
Fig. 36
Rocker
Arm
Cover
Fig. 37
Spark
Plug
Hole
Adjusting Nuts
Feeler Gauge
Rocker Arms
Fig. 38
INTAKE
EXHAUST
Checking the fuel, cleaning the air filter, and adjusting the idle
speed should solve most engine problems. If not and all of the
following are true:
• the engine will not idle
• the engine hesitates or stalls on acceleration
• there is a loss of engine power
Have the carburetor adjusted by an authorized service dealer.
ROCKER ARM CLEARANCE
This requires disassembly of the engine. If you feel unsure or
unqualified to perform this, take the unit to an authorized
service center.
NOTE: Inspect the valve to rocker arm clearance with a feeler
gauge after the first 10 hours of operation and then every
25 hours of operation thereafter.
• The engine must be cold when checking or adjusting the
valve clearance.
• This task should be performed inside, in a clean, dust free
area.
1. Remove the muffler cover by pressing down on it,
separating it from the engine cover. Using a flat blade
screwdriver, disengage the middle and front tabs and slots
first. The cover will hinge off from the rear tab (Fig. 34).
2. Remove the two (2) screws on top of the engine cover with a
Flat-head or T-25 Torx screwdriver (Fig. 35).
MAINTENANCE AND REPAIR INSTRUCTIONS
Fig. 34
Engine Cover
Front Slot
Front Tab
Middle Tab
Middle Slot
Rear Slot
and Tab
Remove
Screws Engine Cover
Fig. 35
Muffler
Top View Of The Engine