Are you encountering and dealing with low engine oil pressure alarms on your Cummins marine engine but are not sure if there’s something really wrong? This is not as uncommon as you think… if you understand the Cummins engine oil pressure specifications established by Cummins and the nature of a “high-flow, low oil pressure” engine oil design, then you’ll also understand that Cummins alarm set points are basically at or below the minimum rated oil pressure for a reason, although they can cause a lot of grief by having to deal with false alarms.
Mechanical engines are the difficult engines to manage because the accuracy of the sending units, wiring, alarm board (PCB) all play a role in how the information is interpreted. If after a hard run, while backing the engine(s) down to an idle, you’re experiencing intermittent alarms, and you are SURE that you’re still meeting the minimum pressure requirements, you may need to “bump” up the oil pressure signal slightly to raise the pressure indication to just above the alarming point. This can be done by placing a small 5-10 ohm 1/4 watt resistor in-line in between the sender and the gauge. This will “fake” the alarm board into thinking that you have a few more PSI than the sender is actually indicating, making that annoying alarm go away when backing down. Refer to the graphic as an example of how to install the resistor.