Yamaha F15A Owner's Manual page 56

cC
8 Do not turn the main switch to
"START" when the engine is running.
8 Do not keep the starter-motor turning
for more than 5 seconds. The battery
will rapidly become exhausted and it
will be impossible for it to start the
engine. If the engine does not start
within 5 seconds, return the main
switch to "ON", wait 10 seconds, and
then crank the engine again.
3-15
E