1983 Mainship Mk III Trawler: Oil Pressure Sensor

The oil pressure guage on my Mainship suddenly shot off the scale and stayed there. Having checked the wires, my mechanic tells me that the oil pressure sensing unit needs replacement. It appears that when Mainship ordered Perkins Diesels from England, they were ordered without guages. Mainship installed their own according to the very helpful "Kenny" at Minnesota Perkins parts outlet JT Services. Note that JT shows a part #185246180 but Kenny maintains that it is a PERKINS sensor and will probably not work on my Mainship installation. My boat has the original Perkins ST6.3544M 200 HP turbo engine.
The boat is sitting at the dock and July is streaking by!

Has anyone been through this? What sensor unit do I order?

My Thousand Islands area freshwater Mainship has been redone and looks almost new outside. "Teak"cockpit. Custom forward cabin. New Vetus. New 6 kw. Kohler. Awlgrip. Nova Kool chest fridge/freezer.No rot. 2800 hours on Perkins.

I bet you have a duel station and it's a VDO gauge, correct.

The sender needs to be a duel station sender and the problem you have is most likely a bad gauge or a loose wire to one of the gauges. The ohms are cut in half with the loss of resistance of one gauge so the value doubles and send the other gauge to full scale.

I replaced both gauges and the sending unit until I found a bad connection up stairs.

1983 Mainship MKIII Trawler Oil Pressure Sending unit

Thanks for imput.
This model Mainship does indeed have two stations but the lower station was not fitted with an oil pressure guage. Wires were checked. I am not at boat so do not know offhand the brand of guage.
Note the way we Canadians spell guage....LOL.

When I bought my ride 2 month ago, the sender for the inside helm gauge died. The end connector on the gauge butt just went. Off and I was unable to fix it, so I searched for a new one.
I do not bknow on your engine but on mine it is pretty simple and it is kinda like plumber. The engine port for oil pressure isnfitted with a T and 2 sender are screwed, one for upper helm, one for lower helm.
The only thing I needed to care about was the gauge max scale, some sender are for 80psi max gauge and some are for 100psi max gauge. I ordered the part from marine outfitters in Kingston ON and itb was a 5 minutes job to replace it. Unscrew the old one, screw the new none, connect the wire and here we go.
From my search I know that some engine have specific senders but old engine generally use the same as the one I needed. If you post a picture of your sender I can tell you if it is the same as mine.
By the way when the sender fails, the symptoms is that the gauge is going nuts showing the extreme max as the sender and gauge are based non resistance, when the sender fails resistance is at its maximum.

Perkins Oil Pressure Sensor

Access to my sensor is out of range for me and I am reliant on my (smaller) mechanic. I have found on line a PDF file that illustrates four Perkins sensors.
Will compare same to my sensor when I can lure mechanic to my dock. Marine Outfitters here in Kingston is indeed a well stocked service oriented business.
Thanks for imput.

The sender needs to play nice with the gauge. VDO has a weird (EU) ohm scale that is different then standard, be sure you get the same Ohm rating.

83 Mainship 34 III Oil Pressure sensor switch

The existing unit was a Chinese truck part installed many years before. It was a chore for mechanic to remove it due to difficult access and the fact that part of the assembly spun while they tried to wrench it out. It turns out that my problem was somewhat minor in that upon placing the old part upon a counter of a car/truck parts supplier they were able to provide a replacement easily. The new one is a STANDARD brand truck part, made in Mexico. Turns out the operating pressure is marked on the unit and it is only necessary to get the same thread. A younger, smaller guy could have done the job himself. It was a learning experience. I tend to try to always use O.E.M. parts when possible. Turns out it was causing me an issue here when it was unnecessary.

Thank you to those who responded. Problem solved.