Alarm buzzer

[seaway]

Mercruiser 7.4 mpi S.N. 0L655251. My ECM is a MEFI 3.(DELPHI 16237009). My problem is audio buzzer sounds just after engine start, 1 second on and 3 seconds off coutinuous . I replaced coolant sensor and checked the wires. I replaced drive lube tank and checked the wires. I grounded and ungrounded the oil pressure switch wire. I do not get any fault codes. I sent the ECM to MEFIburn.com
and they said it checked ok. Thanks for any help.

[shrew]

Gear Lube sensor or IAC??

[seaway]

I plan to check the gear lube sensor wires today. Thanks