It's possible you have a bad oil pressure switch. Fairly common problem depending on the year.
The earlier years didn't monitor the oil pressure at idle, only at 2500 or so (I don't recall the exact rpm)
so they will start fine, idle fine but when you take off, they will trip the alarm. Incidentally it usually happens when the ski is on an angle because you under power & it can be intermittent. so it makes you think its an oil level issue, but by design the main oil pump pick up is always in an oil bath. It would have to be really low on oil to not be.
I'm not real familiar with the late models electronics though, they might have changed a bit form earlier ones?