Echo CS-670 Operator's Manual page 17

END OF THE GUIDE BAR may be placed at
the height of about 35 cm.
Rear handle should be gripped lightly with
the right handle.
35 cm
17
AUTOMATIC CHAIN BRAKE
The automatic chain brake stops the operation of
the saw chain in such a manner that kickback
action produced at the end of the guide bar
automatically actuates the chain brake.
To make sure that the automatic chain brake
operates properly, proceed as follows:
1) Stop the engine of the chain saw.
2) Operate the front and rear handles with hands
(grip them lightly), so that the guide bar may be
placed at the height of about 35 cm as shown in
Fig.
3) Softly detach the left hand from the front handle,
and touch the end of the guide bar against the
wood or the like placed below so that the
machine receives an impact.
(* At this time the rear handle should be gripped
lightly with right hand.)
4) The impact is propagated to the brake lever,
which actuates the chain brake.
(PRECAUTION)
When checking the operation of the automatic
chain brake, use a soft surface substance like wood
to provide the impact so the chain is not damaged.
CS-670