I was doing recent dash work (on the trailer and on ground/shore power) and when I turned the port ignition key "on" without firing up the motor, a high pitched alarm sounded after about 10-15 seconds (emanating from the upper port side of the dash panel).
Is this normal?

Completely normal.

That's the oil pressure/hi-temp alarm. The system uses a capacitor to delay the circuit's operation during startup. Once the capacitor reaches full voltage, it powers the buzzer. The sensor (in this case the oil pressure sensor) is closed/going to ground due to the lack of oil pressure while working on the dash.

Yep. This occurred for me with engine running as my oil pressure SWITCH (not sensor, there are 2) failed.

Thanks...I have the books for my boat but I cannot seem to find a summary of all the bells/whistles.

My 2001 came to me severely neglected.. someone even cut the alarm wires! (oil pressure switch failed).

I had to become my own "expert" mechanic using the factory service manuals. Ask away

http://media.channelblade.com/EProWe...ng%20horns.pdf

FABULOUS!!!
Thanks