Cummins marine gen set oil pressure high/low

[Couch910]

While running the Cummins Onan MKDBH marine generator the oil pressure suddenly started to fluctuate between high pressure and low pressure. It was concerning because I have never had this issue. It was running normal and while monitoring it periodically I noticed the oil pressure bouncing from high to low. I decided to shut it off and do some research. Please help, thanks.
TC

[SailingHarmonie]

When you say oil pressure bounces, I assume you mean that the high and low alarms trigger alternately?

If that it the case, it is almost surely an electrical fault, and I would look there first. Are these single wire sensors grounded to the block? Or isolated two wire sensors?

[GordMay]

Apart from the obvious [low or leaking oil], a common cause of an oil pressure gauge fluctuating, is a faulty sending unit.
The sending unit has a small [pickup] tube, that goes to the oil pressure gauge. Over time, these tubes can become clogged, or damaged*, causing the oil pressure gauge to give inaccurate readings, and/or fluctuate erratically.
* Aerated oil [from a cracked pickup tube] can also cause some bizarre issues.


You might also be interested in: “Basic Engine Gauge Theory and Testing”
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