Troy-Bilt TB20DC - Manual (Page 15)

15
MAINTENANCE AND REPAIR INSTRUCTIONS
Check Fuel Mixture
Old and/or improperly mixed fuel is usually the reason
for improper unit performance. Drain and refill the tank
with fresh, properly-mixed 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 and
change the air/fuel mixture. 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 mixture 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.
CARBURETOR ADJUSTMENT
The idle speed of the engine is adjustable through the air
filter/muffler cover (Fig. 30).
NOTE: Careless adjustments can seriously damage your
unit. An authorized service dealer should make
carburetor adjustments.
The cutting
attachment may spin
during idle speed adjustments. Wear
protective clothing and observe all safety
instructions to prevent serious personal injury.
WARNING:
Idle Speed Screw
Fig. 30
If the spark arrestor
hood and spark
arrestor screen are not tightened securely,
they could fall off causing damage to the unit
and possible serious personal injury.
WARNING:
Fig. 29
SPARK ARRESTOR MAINTENANCE
1. Remove air filter/muffler cover. Refer to Removing
the Air Filter/Muffler Cover.
2. Locate the muffler, but do not remove it. Find the
screw on the bottom of the muffler (Fig. 29). Remove
the screw using either a torx #20 or flat blade
screwdriver.
3. Carefully pry up the left side spark arrestor hood.
Two tabs act as hinges on the right side of the hood.
Flip open the spark arrestor hood like a door and
then pull its tabs out of the muffler slots.
4. Using a small flat blade screwdriver, carefully pry the
spark arrestor screen out from the inside of the spark
arrestor hood.
5. Clean the spark arrestor screen with a wire brush.
Replace it if it is damaged, or if you are unable to
clean it thoroughly.
6. Reinstall the spark arrestor screen snugly back into
the spark arrestor hood.
7. Reinstall the two hood tabs into the two muffler slots
and flip the spark arrestor hood closed.
8. Replace the screw you removed in Step 2 and tighten
it securely.
9. Reinstall the air filter/muffler cover.
Spark Arrestor
Screen
Spark Arrestor
Hood
Screw
Muffler
Engine
Tabs
Slots