Chain Brake; Troubleshooting Chart - Stihl 009 User Manual

STIHL 009, 010, 011
2.1.2

Chain Brake

The chain brake is a spring-loaded
band brake without any friction linings.
Its main components are the brake
band, tension spring, hand guard and
the lever system.
The chain brake is actuated via the
hand guard which can be used to
disengage or engage the brake.
2.2

Troubleshooting Chart

Condition
Saw chain turns at idle speed
Excessive chain sprocket wear
Saw chain does not stop
immediately when chain brake is
actuated
The chain brake is disengaged by
pulling the hand guard back toward
the handlebar. This movement is
transmitted via a lever system which
preloads the tension spring and re-
leases the brake band.
The actuating lever, which is attached cluch drum and saw chain are
to the hand guard, remains locked in
the idle position after the operator
releases the hand guard.
Cause
Engine idle speed too high
Clutch broken
Incorrect chain tension
Tension spring broken
The chain brake is engaged by
moving the hand guard toward the
bar nose. This movement unlatches
the locked brake lever and causes
the brake band to be clamped
around the clutch drum by the force
of the preloaded tension spring. The
brought to a standstill in a split
second.
Remedy
Readjust at idle speed
adjusting screw
Fit new clutch
Tension chain correctly
Fit new tension spring
8