1984 OMC Oil pressure sending unit

[Mr Tig]

In my boat this past Saturday. Look down and no oil pressure. Shut the motor off, have my buddy tow me to shore. Get a mechanical gauge, I have gobs of oil pressure. Test gauge as per Seloc manual, gauge is fine. Replace sending unit, gauge pegs out. Question: Do I need to get an OEM sending unit? Are sending units gauge specific? This is on a 1984 OMC 5.7 in a 21' Celebrity boat. Hate to put a mechanical gauge in it if I don't need to.

 

[WizeOne]

Re: 1984 OMC Oil pressure sending unit

how did you test the guage?

 

[Mr Tig]

Re: 1984 OMC Oil pressure sending unit

SELOC said to ground the wire to the sending unit and it should max out at 80PSI. Pulled the wire and grounded it and the gauge went to 80 PSI.

 

[Bifflefan]

Re: 1984 OMC Oil pressure sending unit

sending units are gauge specific as long as, the gauge is the same it came with. If you run a mechanical gauge to it and you have good pressure, and the gauge pegs when grounded then the sending unit is bad, or out of spec and needs replaced with the right one.

 

[Mr Tig]

Re: 1984 OMC Oil pressure sending unit

Thanks for the help guys. This has been a big project and the marine
mechanic I had doing the work half a@#ed it. Should have done it myself from the begining.

 

[Howard Sterndrive]

Re: 1984 OMC Oil pressure sending unit

I had the same scary thing happen once.
I immediately replaced the gauge with a mechanical (bourdon tube type) one.
I ran a hydraulic test hose right from the NPT fitting to the gauge in the dash.
I even used a M/F quick connector on the engine in case I ever need to disconnect it.
I hated trusting an electrical gauge.