Honda BF9.9A Owner's Manual page 69

5. STARTING THE ENGINE
Emergency stop switch lanyard
The emergency stop switch lanyard is provided to stop the engine immediately
in the event the operator should fall overboard or away from the controls.
The emergency stop switch clip must be engaged with the emergency
engine stop switch or the engine will not start. When the emergency stop
switch clip becomes disengaged from the emergency engine stop switch the
engine will stop immediately.
The emergency engine stop switch should not be used to normally stop the
engine. Use the ignition switch to normally stop the engine.
Attach the emergency stop switch lanyard securely to the operator when
operating the outboard motor.
EMERGENCY
A spare emergency stop switch clip is
provided on the remote control box.
SPARE EMERGENCY
STOP SWITCH CLIP