low oil alarm on Yamaha OB

[2000Fisherman]

I recently purchased a 2000 Yamaha 150 V-max OB. The first few times (right out of storage)i started it hooked to a garden hose the low oil alarm sounded when i turned the key but went off right away after the motor started. This i believe is normal. Just recently at the lake when starting it the alarm never sounded. When i turned the key the overheat and low oil light came on but then went off but no alarm. Is the low oil alarm always supposed to sound when starting the engine??