Oil Pressure Gauge

[smthsaln]

Great forum, thanks to all! This is my first post, after years of wanting I'm finally getting my first boat, a 1999 Wellcraft Martinique 2600 with a MerCruiser 5.7, I'll pick it up next weekend. Anyway, the only thing wrong with it is the oil pressure gauge isn't working. Wondering how I can determine if it's the gauge or the sending unit, any quick ways to check? Thanks in advance!

 

[Laddies]

Re: Oil Pressure Gauge

Short the sender to ground and the gauge should read full scale--Bob

 

[smthsaln]

Re: Oil Pressure Gauge

If I'm not mistaken that's the position the gauge is, max. That would indicate a shorted sending unit?

 

[Silvertip]

Re: Oil Pressure Gauge

Either the wire between the sender and gauge is shorted, or the sender itself is internally shorted.

 

[rattana]

Re: Oil Pressure Gauge

Disconnect the wire at the sender, turn the ignition on. The gauge should read minimum pressure. If it does the sender is faulty. If it still reads max, the wire between the sender and gauge could be grounded. Disconnect the signal wire at the gauge, if the gauge still reads max with the ignition on, it is the gauge that is faulty.

 

[waterone1@aol.com]

Re: Oil Pressure Gauge

I just have one question, has anyone put a manual oil guage on this engine or otherwise verified that it is getting good oil preasure ? I realize that it would most likely be making all kinds of noise if it were real low. I'm just wondering if you are sure that the oil preasure is within operating range before you pickup/ or pay for this used boat.

 

[trog100]

Re: Oil Pressure Gauge

waterone1.. first thing that went thru my was that.. especially if the boat hasnt been taken on a high speed test.. thick cold oil hides all sorts of nasties..<br /><br />trog100

 

[smthsaln]

Re: Oil Pressure Gauge

Thanks to everyone for the responses! To manually check the oil pressure do I remove the sending unit and screw in the gauge there? I did take it on a sea trial, but it was mostly at idle speed due to it being in a manatee area.

 

[waterone1@aol.com]

Re: Oil Pressure Gauge

Yes, you can unscrew the sender and screw in a manual guage. I don't like to sound paranoid, but to most of us a boat is a major purchase. I would check the oil pressure and insist on a propper sea trial at the bare minimum. It just makes me a little suspicious that the oil guage hasn't been repaired by the previous owner, I wouldn't think of running a boat without the oil pressure and temperature guages working. By the way if that boat is equiped with the audible alarm or if it is fuel injected, there is a secondary oil switch which will either sound an alarm or shut the engine down if oil pressure falls below the bare minimum (MPI model) we would need the engine serial number to know exactly what you have.

 

[smthsaln]

Re: Oil Pressure Gauge

Appreciate the quick response waterone1, I'll either check out the oil pressure myself prior to handing over the check or have it looked at by a mechanic. The engine serial number is 0L083411.

 

[waterone1@aol.com]

Re: Oil Pressure Gauge

From your serial number, that is an EFI (electronic fuel injected) engine. There are two oil sensors, one is a sender which feeds the oil pressure guage and the other is a low oil pressure switch that tells the ECM (electronic control module) if the oil pressure is dangerously low. Unless you are very familiar with boat engines and are able to take a full sea trial (running the boat at all speeds) I strongly suggest that you pay a tech to give it the once over. A compression test and scanning the ECM for any current trouble codes would be very important.

 

[smthsaln]

Re: Oil Pressure Gauge

Very much appreciate your suggestion waterone1, I'll do as you suggest.