Echo CS-4910 Operator's Manual page 23

CS-4910 DESCRIPTION
H
G
C
F
B
E D
Improper sprocket guard assembly can result in serious injury,
and will cause severe saw damage if unit is started. Never start
or operate saw if brake band is not in place on clutch drum.
Always check chain brake operation after replacing sprocket
guard. Do not use saw if chain brake does not function properly.
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