Troy-Bilt TB465SS - Manual (Page 9)

9
MAINTENANCE AND REPAIR INSTRUCTIONS
CARBURETOR ADJUSTMENT
The idle speed of the engine is
adjustable. An idle adjustment screw
is reached though a hole in the top
of the engine cover (Fig. 29).
NOTE: Careless adjustments can
seriously damage your unit.
An authorized service
dealer should make
carburetor adjustments.
Check Fuel
Old fuel is usually the reason for
improper unit performance. Drain
and refill the tank with fresh fuel prior to making any adjustments. Refer
to Oil and Fuel Information.
Clean Air Filter
The condition of the air filter is important to the operation of the unit. A
dirty air filter will restrict air flow. This is often mistaken for an out of
adjustment carburetor. Check the condition of the air filter before
adjusting the idle speed screw. Refer to Air Filter Maintenance.
Adjust Idle Speed Screw
If, after checking the fuel and cleaning the air filter, the engine still will
not idle, adjust the idle speed screw as follows:
1. Start the engine and let it run at a high idle for a minute to warm up.
Refer to Starting/Stopping Instructions.
2. Release the throttle trigger and let the engine idle. If the engine stops,
insert a small phillips or flat blade screwdriver into the hole in the air
filter/muffler cover (Fig. 29). Turn the idle speed screw in, clockwise,
1/8 of a turn at a time (as needed) until the engine idles smoothly.
NOTE: The cutting attachment should not rotate when the engine
idles.
3. If the cutting attachment rotates when the engine idles, turn the idle
speed screw counterclockwise 1/8 of a turn at a time (as needed), to
reduce idle speed.
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. 30).
WARNING: The cutting attachment may spin during idle
speed adjustments. Wear protective clothing and observe all
safety instructions to prevent serious personal injury.
Idle Adjustment Screw
Fig. 29
9. Replace the fuel cap if it was removed.
WARNING: To prevent serious personal injury, make
sure the cutting attachment has stopped rotating before
you turn it off and set it down.
2. Remove the two (2) screws on top of the engine cover with a Flat-
head or T-25 Torx screwdriver (Fig. 31).
3. Remove the screw behind the engine cover (Fig. 32).
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 (Fig. 31).
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. 33). 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. 33)
• 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 clear-ance
between the valve stem and rocker
arm (Fig. 34). Measure both the
intake and exhaust valves.
Fig. 30
Engine Cover
Front Slot
Front Tab
Middle Tab
Middle Slot
Rear Slot
and Tab
Remove Screws
Engine Cover
Fig. 31
Muffler
Top View Of The Engine
Screw
Fig. 32
Rocker
Arm
Cover
Fig. 33
Spark
Plug
Hole