Yamaha F150D1 Owner's Manual page 57

 The engine speed will automatically de-
crease to 2000–3500 r/min. The low oil
pressure-alert indicator will light or blink.
 The buzzer will sound.
ON
OFF START
If the alert system has activated, stop the en-
gine as soon as it is safe to do so. Check the
oil level and add oil as needed. If the oil level
is correct, consult your Yamaha dealer.
ZMU01828
ON
OFF START
ZMU04584
Engine control system
51