How to troubleshoot and fix low oil pressure alarm?

[Jim Hardesty]

It turns out one of the prongs on the old switch had broken off which was sounding the alarm.

That's the same thing that happened to mine. 

[Jack Hutteball]

Based on your hull numbers, mine must be ready to go!

Jack

[Jim Hardesty]

Based on your hull numbers, mine must be ready to go!

I don't think that it's a wear thing.  IMHO.  I think that the bayonet contacts got bent or damaged at assembly.  That's the only thing that I see that would cause it to break off.
Jim

[sailaway]

Been having trouble with alarm not sounding when I turn the key on. Wondered where the oil pressure sw was. This is a great website. OK the Right p/n is 15841-39010 I have a M-25 or Kubota engine D850 Charlie

[KWKloeber]

Been having trouble with alarm not sounding when I turn the key on. Wondered where the oil pressure sw was. This is a great website. OK the Right p/n is 15841-39010 I have a M-25 or Kubota engine D850 Charlie

Charlie,

Kubota p/n 15841-39010 is NOT for the OEM M-25 (the switch is mounted on a machined block mounted above the Hx bracket.)  The M-25 OE switch is an NPT thread; p/n 15841-39010 is a JIS thread, which is the switch located on the engine block (JIS thread) on the M25-XP. 
DO NOT thread one into the other, even if it seems like it fits the thread.

see....
http://c34.org/bbs/index.php/topic,9168.msg66816.html#msg66816

-kk

[KWKloeber]

Been having trouble with alarm not sounding when I turn the key on. Wondered where the oil pressure sw was. This is a great website. OK the Right p/n is 15841-39010 I have a M-25 or Kubota engine D850 Charlie

There can be several causes of non-alarm, the switch is probably the least likely because it's normally CLOSED (alarms) and opens under pressure.  More likely the wiring is bad, or the alarm module, or........

Do you have an M-25 parts manual?

-kk