Catalina 34

General Activities => Main Message Board => Topic started by: John Langford on September 04, 2018, 07:22:05 PM

Title: Mk II oil pressure alarm
Post by: John Langford on September 04, 2018, 07:22:05 PM
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 doesnít 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.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 04, 2018, 07:30:01 PM
John

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

-k
Title: Re: Mk II oil pressure alarm
Post by: Paulus on September 05, 2018, 04:38:34 AM
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
Title: Re: Mk II oil pressure alarm
Post by: Jim Hardesty on September 05, 2018, 04:45:08 AM
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
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 05, 2018, 12:25:01 PM
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 ďoldĒ engines, and the ďBĒs AND AS WELL some of the ďAĒs and ďACĒ 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 Iíve 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 thatís their choice ó but I prefer to lead you down the correct and shortest path, not necessarily based on what the ďmajorityĒ of boats have for a given year or what one owner has on their boató 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.
Title: Re: Mk II oil pressure alarm
Post by: Jon W on September 05, 2018, 01:02:12 PM
Hi John take Kenís advice. He can save you both time and money in these types of things. Plus you learn more about your boat along the way.
Title: Re: Mk II oil pressure alarm
Post by: Paulus on September 05, 2018, 02:01:27 PM
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
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 05, 2018, 02:55:17 PM
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 ďoil pressure galleryĒ 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 canít 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 doesnít make any sound either, I am looking for another explanation.
Title: Re: Mk II oil pressure alarm
Post by: Paulus on September 05, 2018, 04:18:18 PM
John, you might want to check the ground wire from panel to engine block. 
Paul
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 05, 2018, 04:20:18 PM
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.  :shock: :shock: :shock:

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.

(http://c34.org/bbs/index.php?action=dlattach;topic=9214.0;attach=6168;image)

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
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 05, 2018, 04:28:35 PM
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
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 05, 2018, 04:40:02 PM
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
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 05, 2018, 09:13:44 PM
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.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 05, 2018, 10:50:13 PM
John

Ahhhh another pc of info. A rubber boot, to my knowledge, was not OEM from Westerbeke. I ďremanufacturedĒ 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) 1/4Ē 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 thatís 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 ďPackard 56Ē terminal (by Delphi) which is a true spring-loaded female terminal. (And the male counterpart is actually also spring loaded!!)

Hereís 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 (shouldnít 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 😕
 Iím 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???
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 05, 2018, 11:38:43 PM
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.

Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 09, 2018, 01:57:09 PM
Hi Ken
Not a boot, it turns out, but a some tight wraps of electrical tape over the two alarm switch spade fittings. Sorry for the misleading information but, as you are aware, I am working from feel alone.
 
I have now uncovered the two terminals on the switch and determined that the single wire terminal connection to the fuel pump positive terminal is good. No break in the wire. The schematic says that one of the two leads from other terminal goes via the ďexcitationĒ terminal on the alternator to the alarm buzzer and the second goes to the key switch. The integrity of these two connections is proving more difficult to sort out. I will work on it and report back. The alternator connection will be hard to test because with an external regulator the alternator wiring is harder to sort out. For me at least. With long leads on the multi tester I might be able to sort it out.

The key switch connection raised a question. Since the failure of the alarm to sound regularly every time I turn the key or stop the engine I have had it come on momentarily on a few occasions when I turn the key switch to the on position but before I engage the glow plugs. Is there any chance that the intermittent sounding of the alarm could be the fault of the key switch rather than the wiring at the alarm switch? I should add that since the failure of the alarm circuit, the alarm has never sounded, even intermittently when I stop the engine.

Final thought. As I work on this with your help I canít help but reflect on what this kind of detective work would cost and how unsatisfactory the outcomes might be if I had to hire a mechanic not particularly familiar with Universal engines to solve this problem.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 09, 2018, 06:21:38 PM
J

Ok
Whoever wrapped it may have been aware of the broken tab issue and did that to help protect the oil switch.

Pull the terminals off the oil switch and tape them so they donít ground out, itís the same as zero oil pressure and youíve temp taken the oil switch totally out of the equation. Of course make sure the tabs are ok.  If no change (still weak/no alarm) then presume that thereís a different cause than the oil switch (it doesnít turn ON the alarm, it turns the alarm OFF; see below.)

I feel your pain about access.

The key switch delivers 12v to the oil switch first, then (via the dual wire terminal) to the alt field excite terminal. Then (via a dual wire terminal there) 12v is fed back to the alarm + terminal. Itís the stupidest wiring Iíve ever seen. Why not 12v right from the key switch to the alarm? The engineer who designed that should automatically have his license revoked. i.e. the alarm should have 12v to it whenever the key is on, thereís NO POINT in routing it to the oil sw and alt and back to the panel.

SO- I would temp bypass that circuit to take it out of the equation (in fact thereís no reason NOT to make it permanent.  i.e., run 12v to the alarm + terminal from one of your gauge +v posts.)
If all is well (strong alarm) again, it points to that circuit being the issue. If no change (weak/no alarm) then presume that thereís a different cause.

I still feel your pain about access.

How the alarm works (or doesnít in your case) is completely back asswards from how you would think and how it does on the M-35. On the B, the alarm is ďalways onĒ.  Like the M35, it sounds when the alarm P (pressure) terminal is grounded. So on the 35, no oil pressure, the switch closes and then alarm sounds. Easy peazy.

 But your 35B ALWAYS HAS 12v to the alarm and it is ALWAYS grounded, so it ALWAYS alarms. When the oil Sw closes (with +5 psi pressure) the switch closes and BACKFEEDS voltage to the alarm ground (P terminal) via the preheat solenoid. The backfeed acts against (cancels out) the 12 v- ground, and the alarm ďloosesĒ its ground and shuts off. Yeah, HUH?? 

SO, since the alarm is supposed to be always grounded, thatís the other weak point in the system. It might be a bad ground connection (via the 10a auto reset (not allowed by ABYC) fuse and resistor to ground at the preheat solenoid terminal.) fed from the fuel pump via the red wires in the below:

(http://c34.org/wiki/images/e/e3/B-series_no_oil_pressure_condition.jpg)

BTW when you have oil pressure (oil sw closed) the harness is constantly bleeding off current thru that  resistor to ground. HUH, What???  Revoke his license then tar and feather the designer.

Lemme kno what develops?

K
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 09, 2018, 09:05:37 PM
John

PS - yes itís possible that a burned contact in the key switch could cause a weak/intermittent alarm (as could a poor ground at the preheat solenoid as I describe below.) BUT it doesnít compute unless you have power issues with everything else on the panel, as they are all fed thru the same contact. So if your tach, gauges, lights, blower have no issues Iíd not suspect the key switch. But thatís easy to check; just bypass the switch with a jumper to the alarm + terminal.

K
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 10, 2018, 10:23:42 PM
Hi Ken
I did the two tests you suggested. I took the alarm switch out of the circuit and got no sound out of the alarm when the key switch was turned on. I then put the switch back in the circuit, turned the key and provided the alarm with 12 volts from the big red positive wire in the harness terminal in the engine instrument panel. Same thing. The alarm did not sound.

I gave some thought to the rationale for including the alarm switch, alt field and fuel pump in the same circuit. These are all functions that you want to start up before preheating and pushing the start button. Does that make sense?

Does the failure of these tests suggest where else we might look for a problem? One other observation. Having manipulated the two connections to the alarm switch I didnít get the sense that there is a break between the wires and the female connectors to which they are attached.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 11, 2018, 12:29:31 AM
John

To your first question, actually the alt excite and the alarm need to have power just AFTER start they donít need to be powered before start.  But even if they did thereís no earthly reason to run the key switch power to the oil switch, to the alt, and then back to the panel to power the alarm. Power to the alarm COULD come  from anywhere on the panel that gets power with the key on (eg, direct from the key switch I terminal (not recommended), from any gauge light feed (also not recommended) or from any gauge v+ terminal (thatís what I recommend) from the + side of the preheat or start button (both not recommended.). Doing what Wb did, would be similar to powering the gauges by running a circuit from the key Sw, to oil Sw, to the alt, and back to the panel gauges. I appreciate your trying to save the designerís integrity BUT that circuit doesnít even power the fuel pump before start, the pump is initially powered (until thereís oil pressure) by the preheat solenoid. Nope, license revoked, tar AND feather that engineer.

Even tho you powered the alarm right from the panel feed (with no luck,) letís verify that thereís voltage returning to the alarm + terminal (from the alt.). If there is 12v, we can eliminate the (idiotic) roundabout   alarm power circuit (but I would still make the change and power it from right at the panel.)

Keep the oil Sw out of the equation. Thereís no reason to have it plugged in until we find the culpret (remember the Sw doesnít turn ON the alarm, it turns it OFF) so letís just leave it isolated for now.

Also, just to be precise, the break occurs on the switch male tab(s,) not on the harness wire/female terminal(s.) Taping them together probably prevented that from happening ( flexing/snapping off of a male tab.)

Just to ck the alarm, ground the P terminal, it should sound off. If not thereís a different problem.

With good 12v to the alarm, if it sounds when you ground the P term, your symptom then points to the ground circuit being bad. The ground is established thru the 10a auto-reset circuit breaker (bolted to the preheat solenoid I terminal) and thru the resistor to engine ground. (Iím not referring to the 20a manual reset breaker.)  If either the 10a breaker or resistor have failed you have no alarm.  Does the fuel pump run while preheating?  If so the breaker is good, if not the breaker has probably failed. If the breaker is good it may be the resistor has failed. In other words, the breaker only is needed to power the fuel pump (before thereís oil pressure,) but both the breaker and resistor are needed for the alarm to sound.  You can check this by removing the alarm P wire, and check continuity to panel ground with the key off. It shouldnít be an open circuit, nor be zero ohms. Resistance should be a little over 1K ohms. Honestly I donít know where that resistor resides or how itís connected to the preheat solenoid I terminal because I donít have a B engine.

One other test - with the wire to the alarm P terminal removed chk for voltage on that wire with the key Sw on, and then while preheating.

Apologies this is taking the long route to the cause. Yours is the daffynition of ďconundrum.Ē

Come to clearing my senses (CRS,) a customer with an XPB had a physically broken off 10a breaker. That would manifest your alarm symptoms BUT your fuel pump wonít operate while preheating. Maybe you donít even notice if that happens?

Report back!

-k
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 11, 2018, 02:18:01 AM
John

I found a pic of the resistor, it's also on pg 43 of the parts manual, #17.

See the black heat shrink bulge below on the vertical wire left of the solenoid?

The short jumper comes off the same solenoid "I" terminal that the circuit breaker is bolted to (lower right-hand terminal) and goes to a ground bolt (probably the solenoid mount bolt.)

I wouldn't go looking for it unless the test below shows the alarm ground path is bad.  This is really getting off into the weeds as to the cause.

-k
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 11, 2018, 09:32:14 AM
Hi Ken
I am on it today and will report back this evening.

Some potentially useful evidence re the 10amp breaker and resistor. This alarm issue emerged gradually. First it was weak, then intermittent and finally silent except for the very occasional weak sounding and, even then, only prior to startup. During he course of all this (and including the completely silent phase) I was on a cruise and the glow plugs and fuel pump continued to run without problem. But I canít be sure if the pump ran during preheat because I replaced the original mechanical Facet pump last year with the newer electronic version that apparently doesnít tick like its predecessor. I did have a fuel starvation problem earlier this summer but that disappeared when I changed the 2 micron primary Racor filter element. The old one was very dirty suggesting that I might have a sediment problem in my tank. Previous filter elements have lasted considerably more hours. Excuse the possibly extraneous context.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 11, 2018, 10:11:29 AM
PS

That should be ď.... a two micron...Ē.   Damn Seri and the phone she rode in on.

******

I wonder if the guts of the breaker can get corroded? The one in that picture we had to replace, it was in very bad shape.

No problem on the content, will get to the bottom of it. Always good to have more rather than less info.

We can get into it later, but eight to micron is not recommended for the primary filter
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 11, 2018, 03:43:40 PM
Ken,
Re the third test, checking the continuity of Alarm P wire to panel ground. Is it the continuity of the disconnected Alarm P wire or the P terminal when the P wire is disconnected
?
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 11, 2018, 05:20:50 PM
Answered my earlier question. I just finished the four tests.

I measured voltage across plus and minus alarm terminals. Zero reading on P terminal. 0.368v on C just out of interest.

Took the alarm switch out of circuit. Check tabs and they seemed solid.

Grounded the P terminal and got solid alarm signal. Much stronger than usual.

Checked continuity between P wire and panel ground at panel buss bar, 960 ohms.

Voltage on P wire with power on is 0.06 and with preheat added is12.26v.

Finally, canít tell if fuel pump is operating during pre heat. No ticking as noted earlier.

Will send picture of preheat solenoid.

Thanks again for your willingness to pursue this with me. I am learning a lot even if an answer hasnít emerged yet.
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 12, 2018, 09:41:57 AM
As promised
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 12, 2018, 04:23:08 PM
Hi Ken
Reattached the alarm switch and ran the engine just to make sure I hadnít crossed any wires while testing yesterday. No alarm at start up but strangely when I shut down got an anemic oil alarm. Opened the panel and checked the voltage at the alarm and it was 3.78 volts which might explain the anemia. With the engine switch still on and the buzzer still bleating, I checked the voltage at the fuel pump. It was 13.75v. And when I did that test the alarm buzzer stopped sounding and then started up again when I removed the test leads. I went back to the panel and turned off  the engine switch. I then bypassed the ignition  switch and applied power from the positive feed at the buss bar to the P terminal on the alarm switch. Still anemic and under 4v despite being fed from a source measuring 14 volts. Does this suggest some kind of ground issue in the alarm circuit?

Hope those might be a useful observations.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 12, 2018, 10:09:03 PM
John

Iím right smack in the middle of a move, Iíll review the test results and get back ASAP.

-k
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 13, 2018, 08:04:51 AM
No problem Ken. Iím in no rush. The boat works even if the alarm doesnít at this point. This engine hasnít lost a drop of oil in its 20 years of service and I monitor the oil daily when cruising.

I hope you donít hate moving as much as I do.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on September 13, 2018, 09:50:42 AM
As James Clapper described going before Congress, itís a step below trying to fold a fitted sheet.
Title: Re: Mk II oil pressure alarm
Post by: John Langford on September 27, 2018, 07:14:58 PM
I see that you survived your move Ken. If you have any thoughts on the results I posted for the tests you suggested I would love to hear them.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on October 16, 2018, 09:10:27 AM
John, Life intervened, hope this helps:

Quote

Reattached the alarm switch and ran the engine
No alarm at start up but strangely when I shut down got an anemic oil alarm. Opened the panel and checked the voltage at the alarm and it was 3.78 volts which might explain the anemia. With the engine switch still on and the buzzer still bleating, I checked the voltage at the fuel pump. It was 13.75v. And when I did that test the alarm buzzer stopped sounding and then started up again when I removed the test leads.

With (only) the key on, there should be no V to the fuel pump.  The schematic tells me that V is supplied thru the preheat solenoid while preheating.
I wonder if there was residual psi that was closing, or partially closing, the oil switch?

Quote

I went back to the panel and turned off the engine switch. I then bypassed the ignition switch and applied power from the positive feed at the buss bar to the P terminal on the alarm switch. Still anemic and under 4v despite being fed from a source measuring 14 volts. Does this suggest some kind of ground issue in the alarm circuit?

The P terminal connects to the switch, so it seems that there's something robbing voltage.  I wonder if the oil switch is possibly "partially?" shorted to ground and bleeding off current enough that it robs the alarm?  I've never seen that happen but I guess anything is possible. 
The switch doesn't operate through ground (as the single terminal switch does.)  There isn't a good ground from the switch to the engine (thru a painted bracket bolted to the block) but I suppose it's possible that a poor ground exists there.

Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on October 16, 2018, 09:20:42 AM
John

Correction.  With other than 0.0 V at the P terminal, that means that some V is being backfed to (not being bled off from) the alarm, which prevents it from sounding (or is anemic).  I don't know at what V level it is anemic vs totally shut off. 

That back feed might be because there's residual psi (V back fed thru a closed oil switch) or maybe the switch is "leaking" V back to the alarm even in the zero psi (switch open) position?  I suppose you could do a continuity (ohm) test thru the switch terminals, but it's probably just as easy to spin a new one in to see what happens.  If it is a partially "leaking" switch this is the 1st I've run across that (but as you know anything goes in the marine world) they typically just fail in the open position and never get any alarm.  Maybe partially open/closed is the signature just before final failure???
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on October 16, 2018, 09:39:51 AM
John, earlier tests:

Quote

I measured voltage across plus and minus alarm terminals. Zero reading on P terminal. 0.368v on C just out of interest.

Took the alarm switch out of circuit. Check tabs and they seemed solid.

Grounded the P terminal and got solid alarm signal. Much stronger than usual.


Ok, that seems normal. A-0k on the alarm.

Quote

Checked continuity between P wire and panel ground at panel buss bar, 960 ohms.
Voltage on P wire with power on is 0.06 and with preheat added is12.26v.


Ok, that seems normal.  The ohms seem a little low, I would expect 1000+ , but not a problem.  Preheat solenoid is OK, as it is backfeeding V to the alarm as at the same time is powering the fuel pump.

Quote

Finally, canít tell if fuel pump is operating during pre heat. No ticking as noted earlier.
Thanks again for your willingness to pursue this with me. I am learning a lot even if an answer hasnít emerged yet.

At least we know it is getting powered correctly, which is the key.  So. I'd conclude that your solenoid and the 10a fuse, and the resistor to ground (buried inside a heat shrunk wire) is okay.

With your more recent test, this points to the oil switch, but it failing in a fashion that I've never seen before.  Always surprises on a boat I suppose.

If the switch is bad, then that means we're correctly interpreting the troubleshooting results.  As I said before you could test the switch, but not worth the effort.  Just for yucks when you remove it I'd check the resistance across terminals and to the case to see if there is leakage.  if anything but 0.0 ohms (no psi, switch open) then that means that, at zero psi, it's indeed leaking JUST enough voltage back to the alarm P terminal to make it anemic, but not robbing enough V going to the fuel pump to shut it down.  From your panel tests, it appears that about 0.5 V or so back fed is the shutdown level of the alarm?
Title: Re: Mk II oil pressure alarm
Post by: John Langford on October 18, 2018, 11:58:20 AM
Thanks Ken. I appreciate you taking up this file again. I will, in due course, try a new switch and report back.

If the switch is the problem then itís behaviour is erratic, either silent, anemic or full throated. My sense is that it never changes behaviour once it starts up. Itís either anemic, loud or completely silent for that cycle. I have never had it change from one mode to another once it starts.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on October 18, 2018, 12:51:52 PM
John

Yep itís a strange one but you know how that goes on a boat.
I thought the only full howling you got out of it was forcing the alarm at the panel, not relying on the oil switch.
Title: Re: Mk II oil pressure alarm
Post by: John Langford on October 18, 2018, 10:54:07 PM
Yes that was the maximum noise. But I occasionally get a healthy beeping that is easily differentiated from the wheezy anemic mode.

 Bloody hell, we have now developed a spectrum of literary descriptors for the performance of this silly switch. Maybe I need a life🙁
Title: Re: Mk II oil pressure alarm
Post by: John Langford on November 03, 2018, 12:35:49 PM
Just received a new oil pressure alarm switch. I understand that polarity of the switch is not an issue,  but before trying to replace the switch I wondered if the old one can be spun off by hand and the new one spun on the same way. Or is a wrench required for both removal and installation?
Title: Re: Mk II oil pressure alarm
Post by: Breakin Away on November 04, 2018, 06:25:29 AM
Just received a new oil pressure alarm switch. I understand that polarity of the switch is not an issue,  but before trying to replace the switch I wondered if the old one can be spun off by hand and the new one spun on the same way. Or is a wrench required for both removal and installation?
I had a similar problem 2 years ago, and had quite a bit of difficulty getting the old switch off. It was way too tight to get off by hand, and very tough to get a wrench in due to tight confines. You'll find discussion on the topic here:

http://c34.org/bbs/index.php/topic,9214.msg67504.html#msg67504

I ended up using a 1-1/16" crows foot tool:

https://www.amazon.com/gp/product/B002YK7MEG/

I do have a related question regarding an anemic oil pressure alarm. When I first turn my key to the "on" detente position (motor stopped), I get no alarm. If I turn it past to the glow plug position, then immediately let it come back to the detente position, the alarm puts out a healthy beep. This is consistent and repeatable. Is this normal, or is there corrosion or other faulty connection that gets "knocked off" by moving the key to the glow plug position? If it's not normal, what is the suggested fix? Do I need to disassembel the key swtich and clean up the contacts? Could I just squirt some WD40 into the key hole and move it around a bit? (I haven't tried this because I don't want to make a mess that's even tougher to clean up.)
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on November 04, 2018, 08:18:04 AM
John

Thereís a factory bulletin re: the switch and a wrench that you might want to read on the TechWiki (Manuals).

The switch should be installed hand snug plus a turn.

Was yours? Who knows!
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on November 04, 2018, 08:25:52 AM
Breakin

WD40 isnít the best treatment for an electrical switch. Possibly electronic cleaner/lube if itís sticky or dirty.  If the contacts are burned itís toast, and for the cost of a good Cole-Hersee switch itís not worth the time to mess with it much.  Its guts are not user serviceable.
Title: Re: Mk II oil pressure alarm
Post by: Breakin Away on November 04, 2018, 10:39:01 AM
 I guess my main question is whether it is normal for the low pressure alarm to not be active until after you have turned past the detente. Does that mean replacement is needed, or would the replacement just do the same thing?
Title: Re: Mk II oil pressure alarm
Post by: John Langford on November 04, 2018, 11:22:00 AM
Iíve noticed the same phenomenon on occasion. I go through periods when I get silence when I turn on the key, then an anemic beeping after engaging then disengaging the glow plugs. It is not ďnormalĒ as the alarm should sound whenever there is no oil pressure.  BTW, I regularly dose the internals of my key switch with a contact cleaner to no ill effect. A new switch cost about $35.

I have not tried to take off the old alarm switch yet. Thanks for the reference to the tech wiki.

A final note. This alarm switch problem is quite common. Over the last few weeks Iíve talked to a number of 34MkII owners whose alarm has not worked properly for a long time. Maybe only obsessive compulsives worry about it😬😬😬
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on November 04, 2018, 02:11:03 PM
I guess my main question is whether it is normal for the low pressure alarm to not be active until after you have turned past the detente. Does that mean replacement is needed, or would the replacement just do the same thing?

The alarm should sound with the key in the first (ignition) position. The oil switch/alarm is interconnected in a way to the glow plug solenoid, so there could be something going on there when you go to the ďSĒ position. Unfortunately this is just another remnant of the really stupid wiring on the B engines. Ron did the best thing and rewired his XPB to eliminate the faux pas.

Does your fuel pump run in the first position? Or when you return to that position?
Title: Re: Mk II oil pressure alarm
Post by: Breakin Away on November 04, 2018, 07:48:42 PM
I guess my main question is whether it is normal for the low pressure alarm to not be active until after you have turned past the detente. Does that mean replacement is needed, or would the replacement just do the same thing?
Does your fuel pump run in the first position? Or when you return to that position?
I am 95% certain that the fuel pump only runs when the key is turned and held in the solenoid position. It does not run when initially turning the key to first position, or when returning to first position after heating the glow plugs. However, the buzzer does continue when returning to first position, so I guess it's possible the pump continues to run but I can't hear it.

By the way, once the buzzer comes on, it is not anemic at all (hence the "can't hear it" comment about the little ticking pump).

It sounds like I should just replace the key switch, and that should fix the problem. (I know you don't like the wiring scheme, but changing that is above my pay grade.) I'll try shooting some contact cleaner in there first just to try. Is there a good substitute part, or should I just order the genuine Westerbeke key switch?
Title: Re: Mk II oil pressure alarm
Post by: Stu Jackson on November 04, 2018, 08:16:59 PM
I am 95% certain that the fuel pump only runs when the key is turned and held in the solenoid position. It does not run when initially turning the key to first position, or when returning to first position after heating the glow plugs. However, the buzzer does continue when returning to first position, so I guess it's possible the pump continues to run but I can't hear it.>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

It sounds like I should just replace the key switch, and that should fix the problem. (I know you don't like the wiring scheme, but changing that is above my pay grade.) I'll try shooting some contact cleaner in there first just to try. Is there a good substitute part, or should I just order the genuine Westerbeke key switch?

The Critical Upgrades topic discusses how this works in great detail.

Key switch covered in my recent Mainsheet article: 

http://c34.org/Ignition-Key-Switch-Replacement/

This is for a Mark I which only requires an I/O switch, not three position.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on November 05, 2018, 07:01:12 AM
Breakin

Of course thereís no 100% guarantee that itís the switch but itís cheap insurance to replace it. Myself, Iíd troubleshoot to convince my brain that itís the problem, but it all depends on time/ability.

Defender carries C-H ignition switches. From what you describe you have a 3 position.
OFF - ON - MOMENTARY ON
(off / ignition / start)
Panels that have both start and preheat push buttons use the 2 position (OFF - ON) switch.

Get the rubber weather cap for it if the part Defendet has doesnít already include it. Some C-H part numbers include the cap.
Title: Re: Mk II oil pressure alarm
Post by: Breakin Away on November 05, 2018, 07:34:34 AM
Wait.  Wb switch?  Does your engine have a Universal panel or a Seaward panel?
The Seaward panel doesnít have a Wb switch in it.
My boat has the panel at the binnacle under the wheel, typical of MkII boats of my vintage. I don't recall whether it's made by Universal or Seaward - I'll have to check next time I'm there.

I definitely want a switch that comes with a rubber cap (or accommodates one purchased separately). With the key switch at the helm, that seems prudent.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on November 05, 2018, 08:11:42 AM

My boat has the panel at the binnacle under the wheel, typical of MkII boats of my vintage.

Oops didn't notice the mk-ii. DUH

It's a Seaward panel, no Westerbeke part number.


Cole Hersee M-550 Marine Ignition Switch
https://www.defender.com/product3.jsp?id=917256

Item # 204594
(3) Positions: Off - Ignition - Ignition / Start
Ignition / Run: 10 Amps @ 12 Volt DC, (3) Brass Screw Terminals
Key Removable Only in Off Position, Spring Return to Ignition
Model Number: M-550 BP

(https://images.defender.com/images/204594.jpg)

Cole Hersee 83288-BP Ignition Rubber Boot Nut
https://www.defender.com/product.jsp?id=917192

Item # 202098
Chrome-Plated Brass
Self-Closing Rubber Key Slot, Weather Resistant
13/16" - 24 thread
Model Number: 83288-BP

(https://www.defender.com/images/202098.jpg)
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on November 05, 2018, 08:44:47 AM
Does the switch/alarm ALWAYS act as you describe? 

ie, after you flip back from preheat (alarm sounds,) then turn key off and back on - does the alarm sound or not sound?
    - If it's loud I'd initially suspect the ignition switch (messing with the contacts temporarily makes it work)
   
To convince myself whether it's the switch, I would:
     - Carefully pull my panel; not disturbing any switches, wires, etc
     - With a short wire, touch the ignition switch B terminal (heavy red wire) and I terminal (don't know the color but it should be marked.) 
     - If the alarm is loud, I would suspect that the switch is bad.
Title: Re: Mk II oil pressure alarm
Post by: John Langford on November 12, 2018, 02:06:38 PM
I installed a new oil pressure alarm switch over the weekend. It turned out to be not nearly as difficult as I anticipated. The key is removing the front wooden panel on the engine compartment. I then could get a box wrench on the nut used to tighten or loosen the oil pressure sender. Once it was out of the way, I could get large adjustable pliers on the body of the alarm switch and break it loose. I tidied up the small amount of oil that leaked out, installed the new switch and then the old sender, attached the wires to both units and tested the engine.

Unfortunately the new alarm switch didnít make much difference. The oil pressure gauge works fine, but the alarm buzzer still does not sound when the engine key switch is turned to the first position. When the key is turned further just briefly to engage the solenoid and glow plugs, and then returned to the first position, the alarm buzzer sounds. It does not sound after the engine is shut down and the key is left in the first position. I have no idea if the alarm will sound if I lose oil pressure underway. I suspect not.

Ah well, at least with Kenís help  I now know how the alarm system works and I feel more confident about dealing with its various components. I will improve the wiring at the oil switch terminal as Ken recommended and then lick my wounds...literally, as the wrench work in very tight quarters is not easy easy on the old bod.
Title: Re: Mk II oil pressure alarm
Post by: KWKloeber on November 12, 2018, 02:59:09 PM
John

Iíll give this some more noodlin. 

At least your results squares with my analysis that ďitís not the oil sw itself.Ē  Whatever consolation that bring I dunno.

Humor me, itís been a while...  bypassing your key switch did not help, correct?
Iím still thinking - power resistor or preheat solenoid issue, but thatís w/o studying the schematic once again.
Title: Re: Mk II oil pressure alarm
Post by: Roc on November 13, 2018, 03:53:07 AM
John
My alarm does the same thing. Been like that for almost 20 years.  Not always, but sometimes at the first position, no alarm.  Move key up to engage glow plugs, then back down, and alarm sounds.  Sometimes alarm sounds at first position as it should.  Sometimes I need to engage glow plug position more than once and alarm will sound in first position.  It's just random.  Sometimes when engine is shut down, alarm sounds, sometimes it doesn't.....  Also, sometimes when running in gear at low RPM (~1200 or so), alarm chirps.  Increase RPM, chirp goes away.
Title: Re: Mk II oil pressure alarm
Post by: Jim Hardesty on November 13, 2018, 05:46:38 AM
Gentlemen,
Shamrock's alarm always sounds when there is no oil pressure, except when the glow plugs are on.  Never a chirp.  I must have got a very good ignition switch.  On my wish list for the perfect boat would be an oil pressure gage along with the alarm.
I only wanted to report my experience.  Not saying there's anything wrong with the way other boats are.
Jim
Title: Re: Mk II oil pressure alarm
Post by: Breakin Away on November 13, 2018, 08:21:09 AM
As previously reported, my boat has the same behavior as John and Roc. I wonder if Catalina changed components/design between #1535 and #1570.