I have a 1993 Catalina 34 with a M35 engine. My oil pressure switch does not work and may be leaking. I've tried a deep socket and a crows foot, but can't get access to the switch. Do I need to remove the exhaust manifold or is there some secret to removing the switch. Thanks.
Ok, I see there is a Tech Article on this, but I seemed to have misplaced my membership info. Hopefully I can get that corrected.
You might have the elusive switch that you cannot get a socket on.
It seems that there are some exhaust manifolds that are either slightly out of place or maybe the casing is different. I don't see another reason why some can get at the switch and others cannot.
Read this thread
https://c34.org/bbs/index.php?topic=9533.15
I believe that Matt still has his magic socket.
Once you get it out you might consider installing a hose and remote switch (as Wb does on the B engines.)
Yes, I've read that. Maybe the problem is that I have a "generic" switch and it requires a 1 1/16 socket.
Guys : I wrote a Mainsheet tech note article on removing and replacing the oil pressure switch on an M25XP engine.
I pointed out that one of the main problems with the switch was the failure of the joint bond between the metal body and the Bakelite center. I recommender that you clean the new switch and seal that joint with epoxy!!
A few thoughts
Yes Matt does still have the magic deep socket. (If you have a grinder you can one yourself) He was nice enough to lend it to me this year. Its the way to go so you dont have to remove the manifold.
Guys : I know that I use a small 1/4" socket to remove the screw for the wire. That way it was easiest to screw it with the attached wire in to the new sender. Believe that I used a crows foot wrench to loose /remove the old one. Don't remember if that sender was a straight or tapered thread?
Guess I just need to reread my Mainsheet Article !!
A few thoughts
I do have my "magic socket". It's just a cut down socket. Let me know if you need it and i'll ship it out.
On the subject of oil pressure switches, has anyone "Tee'd" the switch and added an oil press gauge? I was thinking of replacing the ammeter gauge with one. Suggestions on parts/ sizes, etc?
Tim : I hope that you, mean Voltmeter and NOT ammeter!!
A thought
I think what Ron was getting at is you should already have a volt meter on your engine panel, not an amp meter. If you don't then your system has not yet been "properly" upgraded. Also, do you have the high temp alarm "upgrade" installed?
https://www.catalinadirect.com/shop-by-boat/catalina-38/electrical/high-temp-alarm-retrofit-m-18-m-25-m-25xp-m-35/
TTim
"Yes."
I've done this 3-4 times.
There's two ways - the first is to remote-locate the switch and gauge sender as Wb did on the "A" engines and is currently on the "B" engines. Wb has a part that's a brass tee brazed onto a bracket that mounts onto the unused engine mount land - there's an angle adapter for the oil port and an extension hose to the bracket.
The remote mount can be anywhere - the original M25s had an extension hose to a block for the oil switch and a gauge sender (an option on Universal engine panels) mounted to the Hx bracket. See #s 11, 20, & 14 below. I moved my switch over to the engine block when at about age 15 the extension hose deteriorated and started weeping.
See the hose, bracket, (2-prong) switch that's on the A engines on the next pic.
The 2nd way is to extend the port with a 1/8" pipe nipple, but the tee should be supported (maybe by a bracket hanging down from a strap bolted to the exhaust manifold studs?) The pipe nipple busting off at the engine block due to the weight/moment arm created could ruin a sailing day.
The port and switch are 1/8" JIS thread (Japanese Industrial Standard) which is functionally the same as 1/8" BSPT (British Standard Pipe Taper.) McMaster carries an adapter and adapter nipples and BSPT fittings.
So you need to either get an NPT switch for the tee or stay with JIS thread and find a JIS/BSPT gauge sender. ###
### (all that said, the key difference is that NPT thread pitch is 27/inch and JIS is 28/inch. So practically speaking you could screw NPT into JIS and *it works* but it's not the *proper* way.
I did that mismatch before I learned enough to realize the engine and oil switch were not NPT pipe thread.)
With these threads in the block being tapered.... can I safely assume that a banjo bolt at the existing oil pressure switch spot won't be an option? That has been my preferred connection where possible.
Ron, yes I meant voltmeter;-)
Noah, I do have the engine temp alarm installed
Ken, thanks for the info. I will definitely start running down those parts.
Tim
Note that the Wb hose (for the XPA) seems an inch or so two too short -- it took adding an additional fitting to shorten the distance between the oil port and tee. Since these are made by human hands it might be an anomaly or just be Westerbeke quality "control." I'd think one could make up a hose locally -- it's relatively low pressure, not like a hydraulic hose.
Ken, yeah I was wondering about that hose. I looked it up on WB's website and it's 70 bucks, just for the hose! Add in the other bits and I think one is in for a couple hundred, easy. I wonder if some hi temp fuel line attached to a barb on either end would be sufficient. Then, of course the length would be customizable. Any thoughts?
Tim
McMaster has many configurations of oil hoses on the shelf if you can find one the correct length in either a 1/8" or 1/4" NPT thread.
https://www.mcmaster.com/Oil-Hose
There's also a stainless braid hose that can be made to length w/ 1/8" NPT ends.
I had also thought that copper tubing with compression fittings would work. There's vibration but zero relative movement between the two points on the engine block at either end of the tubing.
As far as the other end it wouldn't be a big deal to cut out n drill a small 1/8" plate that bolts to the unused engine mount land holes, and have a tee brazed to it. That's all Wb does (then paints it red.). The one I ordered was just a brass tee (flat faces) brazed to the plate.
First of all, thanks for all your help. You people are amazing.
I was finally able to remove the old switch. I had purchased a 1 1/16 deep socket and a crows foot wrench, both of which were not useful. There just was not enough room between the exhaust manifold and the starter.
I then purchased a 1-1/16-Inch Extra Thin Wall Wheel Protector Impact Socket https://www.amazon.com/dp/B006L23AQ2 (https://www.amazon.com/dp/B006L23AQ2) that almost worked.
On my next visit I came prepared with tools to completely remove the heat exchanged, but I tried loosening the nuts first. I was then able to get the socket partially on and after a few taps with a hammer I had enough grip to turn it with a breaker bar and I was able to remove the switch!
I had already purchased a replacement switch, but it also needed a 1 1/16 socket. I went to a couple of marine shops and everything they had also used a 1 1/16 socket. I went to an autoparts store and a very helpful woman let me look at a few switches. I ended up selecting a MasterPro 2-8000 switch as it only used a 7/8 inch socket.
Since it's used for Honda and Nissan, I assume it's the proper thread.
The only other difference was that the MasterPro used a bullet connector. It was easy to install using the 7/8 socket and the alarm sounded properly when I turn the key. Once the engine started, the light and alarm when out. :clap
I took the old switch home and put a ohm meter on it and sure enough it was always open. I had tested the first switch I bought by blowing compressed air into switch to confirm it would open under pressure.
I tried it with the old switch and of course it never closed, but a considerable amount of oil came out, so I'm hoping the switch was the primary source of my oil leak.
I have no idea what pressure is required to open this switch, but when I shut the engine down, the alarm goes off instantly, so it seems sensitive enough. Either way, it's better than a disconnected switch. All told, I spent about $50 on various tools and $10 each for the two switches.
Here a look a the defective switch. Does anyone know if this is the standard switch for the M35? I suspect it's not.
Thanks again for all the help!
PS: the OEM switch is below (thanks to Ron.). Turn you phone or computer monitor 90 degrees to the left to see the Phillips slots on the hex-head machine screw terminal. Ron said it's 7mm hex.
TV,
The old switch is not OEM Kubota, it had been replaced before. The Kubota switch has a hex head/Philips screw so it uses a ring terminal. It opens around 5-9 psi. It takes a 15/16" socket (per Ron.) Did you compare the old to the Kubota switch? Perhaps the non OEM switch caused the issue?
The MasterPro 2-8000 switch is 1/8" NPT (27/inch pitch) The engine block is 1/8" JIS/BSPT thread (28/inch pitch.). So there was a better choice.
Note there's a Universal service bulletin cautioning that using other than a socket made for an oil switch may damage the switch and cause a leak.
KWKloeber,
Thanks. I had no idea my monitor could do that! :shock:
I was hoping the MasterPro was JIS/BSPT, but I guess it's not. Of course I don't know if the previous switch was JIS/BSPT, but I may try and measure it. Either way, the current switch is not leaking and appears to be functioning well. Since the "official" one is $50, I'm going to stick with what I have but I will pick up a spare as well as some 1/8 BSPT Male to 1/8 Female NPT adapters.
Given the design of the oil pressure switch the risk of a catastrophic is very low, even if I did not use a special socket. Given the design of the bullet connection I'm confident I didn't put any pressure on the back of the switch.
TV
If there's a number on the old switch I may be able to find out its thread pitch. There are many aftermarket switches that are JIS/BSPT, ISO, and other threads.
On the new one, it depends on what you want to call "official" - it's an "official" Kubota engine so the official one switch a Kb 15841-39013, half the Wb cost
https://www.amazon.com/Kubota-Switch-OEM-Part-Oil/dp/B07B8C5T9J
(these have REALLY gone up - the last cost I have on them was Kb-$18 and WB-$24.
There's aftermarket ones sold for about half the cost.
The number on the old switch is 07317.
tvor : I thought the M35 oil pressure switch was a 2 prong switch just like the M35BC & M25XPB engines?!?
My thought
The 35 is the same switch/wiring as the 25 and XP.
The 35A is 2-prong (same convoluted wiring as the 25XPA, 25XPB.)
Ken : Thanks, as I know that some 1992 C34s that have a M35A engine! Thought that all the 1992/93 C34s all had the same engine? Guess that Catalina slipped in a few M35s - installed what the factory had!!
A thought
Ron
I'm highly unqualified to know which 34 model years had which engines, :shock: but understand that the first A engines that Wb produced (25XPA/3-20A/35A, etc.) were in March 1993 (source TOAD universal model history which info I'd imagine came from Wb?) Before then (1990-1993) I'd guess that Wb was still turning out "non A" Universals??
So I'd guess that 93 model yr boats (that would typically have come off the line in 92) that have an A engine, would need to be a late model 93 (off the line after March 93 but before the 93-94 model year switch-over)?? Would that be how you read it?
My understanding is also that all those with the Wb wiring standard (A engines, since that's what the A designates) had the 2-prong switch (since they have the "new, improved, convoluted" fuel pump wiring carried over from the Westerbeke Propulsion Engines) and also on all the As the switch was mounted remotely (although I suppose on some very early As there might have been some bastardization on that particular aspect?)
Ken : The 30hp engine was (as I recall) an option in the 1991 C34 production and standard in the 1992/93 production. I wonder if there isn't a mixture of Medalist and Westerbeke M35 series engines in that time frame!!
That was about the time that Oshkosh (Medalist) was bought out by Westerbeke??
A thought
Ron
I understood that Wb purchased UM in 1990, but am unaware if Wb ran the division in Oshkosh for some period of time or if Wb closed it down ASAP and moved the division/line to Avon. Even if the latter, both locations could have been operating for some period of time while any stock/Kb engines/marine parts were used up. After buying UM it would take some time but not too long (i.e., months not years?) to start producing the A engines (since the difference was basically just a different harness and a handful of bolt-on components (circuit breaker and solenoid, fuel pump, oil hose and bracket for the remote oil switch.) Maybe Wb just continued to produce the non-A engines until at some point it got the "better idea" (an epiphany in 1992? to convolute the wiring) which then came out in March 1993?
Again when specifically relating to what got married into the c34 -- you are the expert there!
Ken
I have a post script for the OP's question. I replaced my oil pressure switch yesterday. I used a 1/2' drive 11/16 short socket => 1/2 to 3/8 adapter => short 3/8 drive extension to a 3/8 ratchet. I reached it from the little access door in the lav. Very easy, took about 10 minutes. I got the switch at a kubota dealer, $25 bucks. Westerbeke wanted $50! My alarm hadn't been working since I bought the boat, finally got around to really troubleshooting it. It was the switch. Working like a charm now. Thanks to all who post all the great knowledge here! I'll eventually add the gauge as discussed above, but I really wanted the alarm working properly for the time being.
Tim,
Glad that worked out for you. I expected my fix to be on the order of 10 minutes, but it's a boat so expectations don't mean much!
Was your defective switch connected or disconnected? Was it leaking? Since mine had been disconnected to silence the alarm it makes sense to me know why it was leaking. Since it was leaking it could not hold enough pressure to short out the switch.
Tom, my alarm had been inop since I bought the boat 2.5 years ago. The switch wasn't leaking, it was just the next logical step in my troubleshooting. Well, the alarm worked a few days ago when I installed the new switch. Yesterday I went out sailing...and voila! No alarm! The warning lights continued to work, but that's it. I went back today, took the panel out and did some voltage testing, everything is fine. I tried to short the switch and it wouldn't work. 20 minutes later when I started the engine....it worked again! I came home today and ordered a new alarm. I checked literally everything else, so I'm out of ideas. I'm not sure how the thing could work one day and not work the next!
Tim
I presume that you have the single terminal switch. If you shorted the switch terminal (or removed the wire terminal and shorted the wire) to ground, then you bypassed the switch. If no alarm, then it's not the switch causing the no-alarm -- because you bypassed it.
Could be a bad (blue) switch wire itself; a bad connection @ the alarm; a bad 12v+ to the alarm; bad engine ground; etc. Once the blue wire (or alarm S terminal) is grounded the switch is taken out of the equation.
Tim,
I spent a good couple of hours testing the alarm light before I figured out the switch was disconnected.
It's very easy to test by getting 12V to the + terminal and then grounding the P (Pulse) or S (Steady?) terminal.
Ken, before I replaced the switch (single terminal) I bypassed it by grounding the alarm itself to my panel ground. It went off. I also cleaned all the terminals and checked voltage at the panel. Ops check good. Checked continuity from the ring terminal that screws into the switch to the wire at the panel. Checked good as well. After replacing the oil press switch, alarm worked. Went out the next day and it didn't work. Ran the engine today for a few minutes, when I shut it off, the alarm worked again. The ONLY other thing I can come up with is that the voltage to the alarm tested at 11.5-11.6V. Is that enough of a drop to make the alarm only work intermittently? Voltage at the key switch itself was 12. I ordered a new alarm. I'm going to install it, AND wire the alarm pos directly to the key switch. Right now it is daisy chained to one of the gauges.
Tim
What's your at rest btty voltage? 11.5 at the alarm is nuts. It should be the same as delivered to the panel.
Thoroughly clean all the terminals. There should be no problem picking up power for the alarm from a gauge (provided they are clean.)
Test the V at several locations -- there must be a high resistance at one gauge terminal or there's a bad terminal crimp on the daisy chain. Do the wire pull-out test (tug on each) to make sure there's good crimps on all of them. If this is the OEM panel wiring the old automobile Stak-On terminals are crap and can be loose or corroded. I had a wire fall out of one on the 12v distribution panel (re-crimped them all.)
I don't know specifically what alarm is in there and its minimum V, but I would guess that it would be under 12v. When you had 11.5v there, did it sound by grounding the terminal?
If the non-alarm is intermittent then its possible that the S wire continuity is intermittent.
Ken, I'll check the batt V when I get back, but I'm sure it's good. It is fairly new and I keep it charged up through an ACR. The start panel wiring, however, is the original with the old automotive type crimps and terminals. I am planning on re-wiring it all in time, but maybe I'll see it there's some bad ones and replace them now. Thanks again. I'll report back.
Tim
I am making an ass/u/mption here that the batty voltage is not during charging for say 10-12 hours and no loads applied to it. With only the key on (gauges being only current draw), you are basically looking at resting voltage (not under-load voltage.) The panel voltage therefore should be near 13v with fully charged wet cells -- there should be near zero loss because there's virtually no current flowing. So if whatever you read at the btty bank isn't the same at the panel, something is amiss. Corrosion (especially on the negative cables) can be the cause as well as poor crimps. Regardless if the battery isn't at resting voltage (has retained a surface charge) whatever is at the bank should be the same at the panel (unless there is a draw down -- something drawing current that shouldn't be "on.")
<<Follow Up>>
I cleaned up, re-crimped, and replaced some of the wires at the engine panel. I wired the alarm "+" directly to the "+" wire coming up from the battery to the panel. Still no alarm. I replaced the alarm. It works now, and is loud enough to wake up the whole marina! I'm glad I dug into this project, as I'm now MUCH more familiar with the workings behind the panel, and will eventually re-wire the entire thing. While I was in there, I did properly re-crimp the wires to and from the start switch, they were looking pretty rough. Thanks for all the help!
Tim
GREAT that you fixed the issue. Your post is so apropos while we're talking about troubleshooting the engine power situation.
Diagnosing is so much more rewarding than willy-nilly replacing parts (like a new, perfectly good oil switch)? LOL :rolling
Diagnose, diagnose, diagnose, then replace.
I do have a few comments (education, not criticism.)
The lead to the alarm belongs on the key switch "I" terminal not the "B" (battery) terminal (or of course can be on the V+ feed to any gauge.)
You hit it right that it was a bad alarm. But before replacing it I would have done one more step to verify it was bad. Putting a 12v bulb in place of the alarm (could use a 12v tester or even use the light on one of your gauges) would show that the circuit was good and the alarm was bad (the only change being you substituted the alarm.)
Engine off/no oil pressure = the bulb lights.
Engine starts/oil pressure = the bulb goes out.
When it comes the time to rewire the panel, ask questions!
- Ken
A friend of mine with a Bristol 45 had an old style fire alarm klaxon attached to the oil pressure switch - talk about waking the dead!! Wow, it really got you attention when he started his engine!!!
A thought
Ken, great points, thanks! I should clarify where I wired the alarm "+". I didn't take it all the way to the key switch. My gauges are all "daisy chained" together with the old original automotive style crimp terminals. The alarm was connected to the end of the daisy chain. I jumped it to the beginning, so the current is flowing directly through new properly crimped heat shrink marine wire to the alarm. A lot of the distribution at the panel uses these AutoZone double spade connectors. (They are everywhere behind the main DC panel too) I'm guessing that eliminating these guys is a priority in cleaning up the wiring?
Tim
Ok, then you powered from after the key switch, not connected to the "+ wire coming up from the battery to the panel." OR were you referring to that while troubleshooting??
Those piggyback adapters are "ok" but you know that I don't use any more connections than absolutely necessary. In my mind those are bush league -- for 1970s, teenager under-the-dash tapedeck installs.
On my boat it seemed that those male/female piggybacks must have asexually reproduced and have taken over EVERYWHERE. I took out some and plan to get rid of them all.
Quick disconnect terminals don't belong on a boat if there is any alternative. Some old gauges on panels I've done had them but all the new gauges I use have #8 post terminals (although the lights are still all quick disconnects.)
But the type of terminal is actually irrelevant. Obviously, one can daisy chain on post terminals using 2 (or 3)
ring terminals on a post.
And with posts OR quick connects you can daisy chain by crimping multiple wires into a ring terminal (or into one quick-disconnect terminal.)
Say that on a panel one uses 16-ga for gauges/lights. 16-ga uses a Blue terminal (nominally good for 2,600 to 4,100 circular mils - CM.)
(3) 16-ga conductors = 7,800 CM, so you use a yellow terminal (good for 6,500 CM to 10,500 CM.)
Sometimes you can fit (2) 16-ga into a Blue. You can play with the wire gauge, terminal size, # crimped together, and how you layout the daisy chain to make it work w/o the piggyback adapters.
So, why Seaward used them is beyond me. They don't save time (need to make more crimps compared to above) and they add cost.
OF COURSE -- this is just for low amp gauges and lights on a panel, I'd not use that method for any higher amperage terminals.
Ken, Great info, thanks! Yes, my plan is to do as you said, eliminate the "bush league" spade connectors, and yep, they are EVERYWHERE. BTW, the alarm "+" is connected after the key switch, not to the run from the battery.
Cheers!
Hey Tim,
I meant to mention that harbor freight has a few different test leads with alligator clips. I find them really handy to keep aboard just to be able to troubleshoot a gauge, lights - anything low amperage.
Or just to be able to clip my multimeter leads to something so my hands are free to fiddle while I'm checking voltage or continuity.