Puzzling oil alarm

[Bolo]

I was motoring along the other day, with my Universal 25XP, humming along at around 2,200 RPM when the oil alarm buzzer went off along with the light coming on. I immediately shut the engine down. First I looked in the bilge under the engine to see if any oil was present and there was none. Then I re-checked the oil level, which I did before leaving the dock as always, and it was fine. I then pulled the engine cover off and looked the engine all over for any signs of oil on or around the engine and found none. So I cautiously re-stared the engine and waited. No alarms. I continued on my way running the engine only up to about 2k RPM. Nothing. I finally ran it up to 2500 RPM and then a little above and nothing. That was two days ago. We're on vacation sailing around the Chesapeake Bay and still no alarms.

Any one ever had this problem or can offer a suggestion? Thanks!

 

[Emerald]

Any chance you were somehow at a really bad angle long enough to momentarily starve the oil pickup? Heeled over motor sailing?

Oil pressure is often regulated by a spring loaded ball - momentarily stuck open?