Help with Low Oil Pressure troubleshoot

jviss

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Feb 5, 2004
6,748
Tartan 3800 20 Westport, MA
Interesting. What was the tach reading?
Idle cold is about 700 - 800. For some reason I don't understand, when hot it idles closer to 1000 (speed control pulled all the way back).

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Afraal

.
May 29, 2023
22
Catalina 310 Flowery Branch
@Ralph Johnstone your assessment was on point! it was an electrical issue. One of the terminals in the Oil Pressure switch is broken. I guess a combination of corrosion and vibration. I did some additional research and I found out that this little switch is one of the "must have" spare parts to keep in toolbox if you own a M25XPB.

This switch was added by Universal as an upgrade for Marine applications, so there is no Kubota part for it. Maybe someone in this forums knows of an equivalent switch from a non-marine application that could be a good fit as well.
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Jun 2, 2004
3,403
Hunter 23.5 Fort Walton Yacht Club, Florida
I'm not suggesting that one in particular.
There are different thread diameter and pitches also some are for warning lights others for guages.
Any decent parts guy (not likely found at Auto Zone) should be able to pick one out of the catalog.
If you have a part number it can usually be cross referenced.
 
Nov 16, 2012
1,053
Catalina 310, 2000, #31 31 Santa Cruz
Part number for switch is 037323 (Universal part #). 1/8” NPT fitting. I added a pressure sensor and gauge to our M25XPB; there’s an 1/8” NPT port right there.
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