Cleaning And Storage - Troy-Bilt TB70FH Operator's Manual

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.
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.
2. Release the throttle trigger and let the engine idle. If the
engine stops, insert a small phillips or flat blade screw-
driver into the hole in the air filter/muffler cover (Fig. 30).
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 mixture, 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.
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