Originally Posted by ggray
Is there anything else that might cause this problem other than a bad oil pump?
It’s exceedingly unlikely the pump is worn to that extent, it’s possible, but I have never seen it myself.
Step one is to verify oil pressure with a gauge.
Once you determine you have low oil pressure then you start with most likely and go from there, starting with the cold oil bypass valve.
Unlikely but a filter if it has a defect could possibly restrict oil, then oil level of course, and grade of oil.
But first step is put a gauge on it, then with a cold motor
crank it up, and write down oil pressure at idle, then advance RPM slowly in neutral before the motor
is hot and write down max pressure it gets to, it should hit an RPM that above that there is no increase in pressure, that should be the oil pressure relief valve setting and checking it’s function. Also write down the RPM.
Then of course go out and run the boat
normally, for say 30 min, then when it’s fully heated up, reduce to idle, let the pressure stabilize, and write down that number.
The senders, shouldn’t be senders, they should be switches, they are an on / off device, not a variable one, if they were senders then it’s possible you have a high resistance wire, but as it’s a switch, that’s unlikely.
What oil and weight are you using?
I’m hoping someone sold you the wrong switch. Not likely but it would be a good outcome