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Replacement Oil Pressure Switch


Apr 2, 2013
Catalina 310 Niagara-on-the-Lake
I have a broken prong on my oil pressure switch, a common problem when reading these posts. I called the local Kubota dealer and he has never heard of Westerbeke or Universal, he needs the Kubota 10 digit part #. The Westerbeke # is 37323 for my M25XPB engine. Can someone help me and cross reference this Westerbeke #? There are many posts here about the issues with this switch, but alternates are not mentioned..... other than see your Kubota dealer. I tried NAPA and Part Source, they looked at me like I had 3 eyes.Thanks in advance.
Mar 20, 2012
Cal 34-III, MacGregor 25 Salem, Oregon
take it out so you can determine the correct threads and take it to the nearest auto parts store and ask for a 4 to 8lb "normal open" oil pressure switch with the same threads as the old one.... it is a common part and should be easy to find.

Tom J

Sep 30, 2008
Catalina 310 Quincy, MA
Years ago, I took mine to a Napa store and the parts guy was able to match it up with what he had in the store. Some clerks know how to use the catalogs to find what you need. Some don't know what an oil pressure switch is. This happened to me recently when I stopped at a Napa store to look for an oil pressure switcher for my sister's boat. The kid at the computer couldn't find any oil pressure switches listed. I think he was looking for oil pressure sensors. Different animal. The older guy behind the desk who works part time knew what I needed, and came out from the back with a couple to compare to the one I had. Nothing he had would work, but at least he tried.
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Jan 29, 2018
Beneteau 411 Branford
The attached are clips from the Kubota engine manual. My Kubota dealer could get any part with a Kubota part number but they could not look up any "Universal" numbers. The manuals are on the Catalina30 website. I had a C30 and kept the data



Jan 29, 2018
Beneteau 411 Branford
To clarify, the manuals were on one of the Catalina30 groups / sites.
I believe you will find that he threads are metric tapered pipe threads that, to the inexperienced, look like english tapered pipe threads.
Mar 6, 2008
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
I got mine at auto store. 5 PSI normally open contacts. That means the contact are open until the pressure reaches 5 PSI, then the contacts close to indicate acceptable oil circulation or pressure.
May 20, 2016
Catalina 36 MK1 94 Everett, WA
westerbeke p/n 299964
Kubota p/n 15841-39010
Or there's many available aftermarket -
You just need a 1/8-28 ("JIS" or "British" tapered thread, not NPT) normally closed switch that opens about 8 psi.