Troy-Bilt TB90BC Operator's Manual page 14

Cleaning the Air Filter
Clean and re-oil the air filter every 10 hours of operation. It is an
important item to maintain. Failure to maintain your air filter
properly can result in poor performance or can cause
permanent damage to your engine.
1. Remove air filter/muffler cover. Refer to Removing the Air
Filter/Muffler Cover.
2. Turn cover over and look inside to locate the air filter. Remove
the air filter from inside the air filter/muffler cover (Fig. 37).
3. Wash the filter in detergent and water (Fig. 38). Rinse the
filter thoroughly. Squeeze out excess water. Allow it to dry
completely.
Air Filter
Inside Muffler
C over
Fig. 37
4. Apply enough clean SAE 30 oil to lightly coat the filter (Fig. 39).
5. Squeeze the filter to spread and remove excess oil (Fig. 40).
Fig. 39
6. Replace the air filter inside the air filter/muffler cover (Fig. 37).
NOTE: Operating the unit without the air filter and air
filter/muffler cover assembly will VOID the warranty.
Reinstalling the Air Filter/Muffler Cover
1. Place the air filter/muffler cover over the back of the
carburetor and muffler. Align the screw holes.
2. Insert the four (4) screws into the holes in the air
filter/muffler cover (Fig. 36) and tighten.
Do not over tighten.
14
MAINTENANCE AND REPAIR INSTRUCTIONS
Fig. 38
Fig. 40
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. 41). Remove the screw using
either a torx #20 or flat blade screwdriver.
Spark Arrestor
Hood
Screw
Spark Arrestor
Tabs
Screen
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.
WARNING:
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.
Engine
Slots
Muffler
Fig. 41