Onan MDKBR diesel genset randomly stops

[Seaqul]

On a 2007 Lagoon 420, I have a 21 kv Onan MDKBR that randomly stops with an error indicator stating low oil pressure. This has gone on for a year. Oil/filter have been changed. The time to stop from start is 30 min to it never stops. Most of the time when it stops, you can clear the error and restart and it will run until I shut it down. All else runs great. I suspect the low oil pressure sensor but do not know its correct functioning. At rest with the wire off I get a 250 ohm resistance when I thought it should be 0. On starting the engine, the voltage across the sensor starts around 2 volts and slowly (or sometimes more quickly) climbs to 3.6 volts at which point the genset shuts down. This voltage seems to be pretty consistent since I start measuring.

On the other hand, the genset will tend to act consistently (time to shut down) until we do a passage. Then it will change to a longer or shorter time or doesn't shut down at all. This makes me think it is some lousy connection but I haven't pinpointed anything. Or do I maybe have a control board problem?

Any suggestions will be greatly appreciated.