Oil Gauge on a '88 SN 2001

[blaize]

I've noticed that the oil pressure gauge has been fluctuating pretty wildly in our 1988 Ski Nautique 2001. When it's in idle it bounces between 15 psi and around 55 psi; once I give it gas it goes higher than that. Every time it goes below 20 psi it sets off the systems alarm.
Is this normal? I had it serviced just a few weeks ago and they put in 5 quarts of 20-50 oil. After that however, the boat was put in the lake without the drain plug and it took on quite a bit of water before being pulled back out; I'm not too sure that that had anything to do with it though.
Has anybody else had this problem on their Nautique? Does it need to be taken in?

Thanks,
Mike

[M3Fan]

Oil gauges, esp in older boats, are known to fluctuate like that. Could be several things- your sender unit for the gauge, a bad ground on the gauge, or a bad gauge. Also could be actual oil pressure fluctuations, but not likely. May want to have it checked out if you don't know how to swap these parts out on your own.