Engine Running Behavior; Lubricating The Gearbox; Replacing The Starter Rope And Rewind Spring - Stihl BT 121 Instruction Manual

Engine Running Behavior

If engine running behavior is
unsatisfactory even though the air filter
is clean and the carburetor is properly
adjusted, the cause may be the muffler.
Have the muffler checked for
contamination (carbonization) by your
servicing dealer.
STIHL recommends that you have
servicing and repair work carried out
exclusively by an authorized STIHL
servicing dealer.
BT 121

Lubricating the Gearbox

N
Check grease level regularly –
about every 50 hours of operation.
N Unscrew the filler plug (1).
If no grease can be seen on the inside of
the filler plug:
N Apply the tube (2) of STIHL gear
lubricant to the filler hole.
N Squeeze 5 – 10g grease into the
gearbox.
N Do not completely fill the gearbox
with grease.
N Refit the filler plug and tighten it
down firmly.
Replacing the Starter Rope
and Rewind Spring
Removing the Fan Housing
1
1 1
N Take out the screws (1).
N Remove the fan housing.
Replacing the Starter Rope
2
3
4
N Remove the spring clip (2).
N Carefully remove the rope rotor with
washer (3) and pawl (4).
The rewind spring may pop out
and uncoil during this operation –
take care to avoid the risk of
injury.
English
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