Mk II oil pressure alarm

[John Langford]

My oil pressure gauge is working but the oil pressure alarm function has stopped operating. I replaced the alarm on the panel itself but it still doesn't sound when I turn the key or stop the engine. I suspect that the oil pressure alarm switch that is hard to access on the port side of the engine.

Has anyone dealt with this problem. Any advice welcome.

[KWKloeber]

John

Again, post your engine info and your panel info so we can help you

-k

[Paulus]

I had to replace my oil pressure alarm switch 3 years ago.  Hard to get at.  I took the start motor off to give myself some extra room.  However, I would remove the sending wire, clean the connection and try it again.
Paul

[Jim Hardesty]

John,
I've replaced the oil pressure sending unit, don't rember that it was that hard.  I've also had to replace my alarm.  My guess is that you have a wiring problem.  The sending unit has 2 outputs both are from the same source, so if your gage works your alarm should work.  I would start at the engine panel, check that the new alarm works (just because it's new doesn't guarantee it's good) then trace wire.  Hope it's just a connector that has worked it's way loose.

Lots of luck and I hope this helps.

Jim

[KWKloeber]

HEY John

I asked that you post both your engine and panel info because:

1) Boats (no matter the MK) do get repowered, and although some on here may know or remember what particular iron granny you have, I did not.

2) The oil switch operation and how they function is different on different engines.

3) They are vastly different between the "old" engines, and the "B"s AND AS WELL some of the "A"s and "AC" engines.

4) You indicated that you have an oil pressure gauge, which indicates you may have a repower, or at least a non standard panel. Seaward and CTY, in my opinion unfortunately and short sightedly, did not as a rule install oil gauges. The alarm itself and wiring of the Seaward panel alarm can be different from the Westerbeke (Universal) or other panel (if an oddballs.)

5) The  engine info provides a clue to what harness you have, and whether the problem lies in the wiring, vs. the switch itself.

6) WITH more complete info sometimes I can suggest a way to troubleshoot and determine the likely cause before tearing into replacing that switch, which is less fun to replace on your boats, than it is on other boats with better access.

7) (Depending on the engine) it is RARE (but not impossible) that the switch is the cause of a no-alarm situation. It usually fails in the closed position (or constant alarm position). But if I knew the engine then I can tell you better.

*******

BTW, Each time I've diagnosed an alarm issue, to my knowledge, I have been correct in the final outcome. I like to cut to the diagnosis/solution rather than head down a rabbit hole with incomplete information, and ass/u/me things based on only the MK or year.  Others on here may diagnose differently, and of course that's their choice — but I prefer to lead you down the correct and shortest path, not necessarily based on what the "majority" of boats have for a given year or what one owner has on their boat— but instead what YOUR SPECIFIC boat has.

I can surely tell you the correct part number but I am neither a Kubota dealer, nor sell Kubota parts because I have no relationship with Kubota.

[Jon W]

Hi John take Ken's advice. He can save you both time and money in these types of things. Plus you learn more about your boat along the way.

[Paulus]

John, read Jim's post and save yourself a lot of grief.  Both Jim and myself have had this issue.  In my case it was simply the sending unit. I fixed this with using some common sense and no lecture.
Paul

[John Langford]

Thanks to all respondents.

First point. The oil pressure information comes from two sources on my boat. The pressure gauge (part of the Seaward panel that was added after delivery of the boat in my case) is fed by a red wire from the oil pressure sender while the red light and alarm buzzer on the panel are connected to a separate oil pressure alarm switch by a wire that is part of the original harness. Both of these sources are clustered together in what the manual calls the "oil pressure gallery" under the starter motor and various hoses on the port side of the engine. I have only seen these features with a mirror but the gallery appears to be a tube from the block with these two sensors coming off it. As far as I can see there is no wiring problem but I would have to get much better access to the alarm switch to be sure. By feel it seems to have two leads coming of of it. I can't tell whether the leads are integral to the switch or whether they are spade fittings that could be pulled apart. The whole area is dry and corrosion free. I was able to check the connection to the oil pressure sender unit close by and it was clean and corrosion free.

As to the rest of the ID questions you posed Ken. This is the original M35BC.  The panel has a tach, a temp gauge and high temp alarm, a fuel gauge and a buzzer. I just replaced the latter as the original buzzer had recently sounded a little anemic at start up before ceasing to make any sound at all. Since the new buzzer doesn't make any sound either, I am looking for another explanation.

[Paulus]

John, you might want to check the ground wire from panel to engine block. 
Paul

[KWKloeber]

John

Ohhhhhh.. an M-35 "B"--  I can't keep up with the three threads going on  LOL!!

The reason your alarm sounded anemic before it died is due to the harness, not the switch or alarm itself going bad.  You had a poor/intermittent connection, and now the harness has broken off one (or both) tabs on your switch.  So blame the harness, instead of the switch. 

So, the "B series" oil switch setup and wiring is COMPLETELY different than anyone who has an XP or similar engine.  Your switch per se itself isn't the cause -- it literally DID NOT FAIL.  It is the wiring harness that is the cause.  If you replace just the switch the same problem will eventually return.

I posted below your oil switch and gauge sender setup so you can see what you're dealing with in the black hole.  They are both screwed into a brass Tee that is brazed to a plate (part #11) that is bolted to the (unused) holes for the rear engine mount (your rear mount is actually on the engine bell housing.)  Both the switch part #17  (has two 1/4" male tabs) and the pressure sender (in place of the plug part #15) screw into the Tee with a couple elbows.



On the B-engines, Westerbeke used NON-marine grade wire, NON-tinned, STIFF automotive wire -- Rather than fine-stranded, flexible, Type III, tinned, marine wire.  The constant vibration of the engine is transmitted through the harness and the movement is passed to the tabs on the oil switch, which eventually (not IF, BUT WHEN) breaks off one or both tabs on the switch.  It will happen sooner or later to virtually every B series engine.

There is an Autozone part #1053 that can adapt onto the oil switch (you have to trim the rubber a smidgeon) to protect the tabs from moving, but I believe it's no longer available (as of the last time I tried to buy one.)  See it Here:

http://c34.org/bbs/index.php/topic,9006.msg65214.html#msg65214

To rewire that circuit is a literal pain in the neck, arms, knuckles, and flesh-eating parts will tear you to shreds.  The wiring circuit ties from the oil switch to the alternator (believe that?) and powers the fuel pump as well.  it is a COMPLICATED wiring mess on the B series, just ask Ron who rewired his XPB to fit the boat, not the boat to fit the engine.

IIWMB I would rewire my circuit with marine wire.  But as I said it is not for the faint of heart unless you really want to do that -- I can explain how (no charge by the way and no lecture.) 

However, you can also clip off the harness and extend it with TYPE III tinned marine wire, so that the vibration is not transmitted to the oil switch.  Also, you want to ZIP TIE DOWN the stiff harness so it doesn't flex and transmit movement to the oil switch. Yes I know, easier said than done with the terrible access.

The female tabs in the harness that go to the oil switch are crimped with TWO wires in ONE terminal, so it's doubly complicated to replicate it. I would make up two 6" pigtails of #16 wire, crimped to 1/4" female quick-disconnect terminals.  Adhesive heat shrink, and FULLY insulated quick disconnects of course. 
The other end; use STEP-DOWN butt connectors -- they CORRECTLY fit two wires in (from the harness) and one wire out (to the oil switch tab.)  If you cannot find them, I have like a gazillion and can mail you two (no charge of course.)  The challenge is stripping and crimping the harness in that awful port access location.

Questions?  Answers are the easy part; Questions raise the doubt - J Buffett, Off To See The Lizard.

-ken

[KWKloeber]

save you both time and money in these types of things.

True Jon.
If the engine info was posted in the profile, the key advice would be DON'T waste money on a new alarm -- it IS NOT the problem!

-k

[KWKloeber]

John, you might want to check the ground wire from panel to engine block. 
Paul

Paul

Though it never hurts to check 12v negatives, on the oil switch (both your engine/panel and John's) the harness ground plays no part in the oil alarm. The harness negative is basically there for the gauges/lights and the blower.  On yours, the alarm ground is the engine block (through the oil switch,) not thru the harness negative.

On the B series, the wiring is back-asswards from yours (and the oil and temp gauges wouldn't read correctly if the negative was bad.)

i.e., if you disconnect the harness ground you can still start the engine and your alarms **should** work, but you'll have no lights/gauges/blower.  (A good thing to remember in case that condition ever happens, go first to the harness negative.)

-k

[John Langford]

Thank you everyone and in particular Ken for your attention to this problem. Today the alarm came on weakly for a moment when I started the engine which I think confirms the faulty wire diagnosis.

Ken, your link to the previous exchange on the switch (which unfortunately did not come up in my search) helps me understand the way the switch is put together. I can feel a rubber boot and two leads coming out of it. Does that mean that if I push the rubber cover back I will be dealing with two spade connectors (one with an intermittent connection) that I can disconnect and redo using more flexible wire? Is there a polarity issue with the switch. That could be a problem as I would be doing this work without being able to see the switch very easily.

PS Sorry for the multiple postings. The server kept refusing to post my original message telling me to try again. Weirdly all of my attempts eventually showed up which I appreciate is confusing.

[KWKloeber]

John

Ahhhh another pc of info. A rubber boot, to my knowledge, was not OEM from Westerbeke. I "remanufactured" only one B harness and it had no boot, just separate female quick disconnects. I suspect, but do not know obviously whether when the dealer did your install w/ the oil gauge added, s/he used a boot (like the one in the prior post).
In any event the switch Wb used has just (2) 1/4" male tabs (completely exposed.)
The switch is electrically isolated from the block and so it DOES NOT matter the polarity, you can reverse the two terminal connections.

Since you have a boot, it makes me question the whether there is indeed broken tab(s?) on your switch. The boot is supposed to prevent that. If you pull off the boot, the female terminals and it should come off as one unit. In other words the female terms are (most likely) molded into the rubber boot.
I suppose if the boot is intact, it may be as simple as one of the female terminals not making good contact?!?!   Try removing it, or better with the key Sw on, wiggling the boot to see what happens. Then remove it and ck the switch tabs. If both are intact then it may be a loose or corroded terminal. I would install whatever you end up doing with a THIN wipe of SuperLube gel (or bulb grease from the auto parts) to stave off corrosion getting to the tabs. If it turns out the terms are ok but the boot worked loose, previously I have recommended a small zip tie around the Autozone boot to secure it in place. I KNOW that's easier said than done in that location!!!

One of the inherent problems with quick disconnects (I call them quick fall-offs) is the cheap female terminals used. They can loosen from engine heat expanding them and vibration.  Anytime I use a QD in a critical location I like to use a "Packard 56" terminal (by Delphi) which is a true spring-loaded female terminal. (And the male counterpart is actually also spring loaded!!)

Here's another really outside the box way.

Crimp UNinsulated (open barrel) female QD terminals on your two pigtails.
Carefully solder each onto a NEW switch.
Adhesive heat shrink over each tab/terminal for a corrosion proof connection.
Install the switch (a little tricky with the pigtails attached.)
Connect the pigtails to the harness using the step-down butt crimps.
Or use a set of FULLY insulated QD terminals to make your connection to the harness. Then the switch can be removed (shouldn't be necessary in your lifetime) without clipping the wires. Those type are totally encapsulated when pushed together, preventing moisture from getting inside, but they can still be disconnected.

- k.  Let me know whatcha find out.  The rubber boot has me a little baffled 😕
I'm in the middle of a move (ugggh!!) but it would be interesting? a challenge?? to beta test something that would work for your situation and would take all of 20 min to put together.

Did anyone else who replaced the B engine switch have a boot???

[KWKloeber]

JOhn

I'm just thinking aloud (if that's permitted) -- maybe we're using "boot" in two different contexts?

I mean a molded rubber Autozone boot like the pic I showed in the prior post.
Do you mean a "loose" fitting rubber boot like might be on a battery terminal or alternator post?

See below, the two harness leads (center of the pic) that go to the switch are just insulated female QD terminals.  At least that's what I am used to.  Maybe your install has a loose "boot" that the leads run through?  In that case, yes, I could see how the stiff harness could still break off the tabs on the switch.