Yesterday the M35 started right up, ran very well for 25 minutes and attained normal operating temp of about 165F, at 1500 RPM and 6.2-6.5kts cruising. Sailed for five wonderful hours in great wind. (Saw 5 other C34's). Furled the genoa poorly in gusty wind. Had the admiral start the engine so I could try again. The engine started right up but with loud screeching noise like a belt or alternator. She saw the temp go to 180F then to the pin and it was running rough, in the span of a few short minutes while I was wrestling the furler in 18-20kt gusts. I suggested she give it fuel to see if it warmed up and stopped the racket, until I could get back to the helm to check it out. The engine shut down on its' own before I could get back to it. When I went back to try, it started rough, and shut down again with screeching. The alternator was showing it was charging. I anchored, let it cool for an hour. Checked again, raw water was coming out the tail, with lots of smoke and screeching continued. Shut it down in less than 30 seconds.
At anchor, instead of grilling up some dinner I:
Pulled and replaced the impeller, the prior on was new this season, and still looked it but I had the Sherwood pump open, and figured why not.
Coolant level was same, about an inch from the top, nice color.
Oil was fine, no froth, no appearance of anything out of order.
Fan belt - seemed fine. Backed off and re-tensioned while I had the engine open. (last year the belt was loose and made a similar, lower volume, noise).
So, the smoke seemed white. Not sure if it relates to the problem. It could be water in the fuel, but I am thinking the fresh water pump because of the screeching.
We sailed back to the dock, in the dark, with 2-3kts wind on the nose. I was done for the day, and the admiral was too.
I will be going back to the boat, just over an hour away. I read Nigel Calder's suggestions in his Mechanical and Electrical manual. Signs of blow-by are absent. I will check the fuel bowl. I recognize it is possible with the deck fill cap I may have water in there if not tightened enough. But the noise leads me elsewhere, to the pump.
Anything else?
WBev : I carry an stethoscope from an old Blood pressure cuff on board. You need to find out where this screeching is coming from and that stethoscope will let you know.
My guess is that your internal water pump may be the culprit!! You also can use an old auto mechanics trick of taking a long common screwdriver and placing the tip on what you are checking and the handle in your ear.
a few thoughts
I think you're on the right path but if the coolant pump was bad I'd expect to see coolant leaking from the front (bearing.). Maybe it hasn't gotten to that point. Grab the pulley sans engine belt, and try to rock it back n forth (laterally not rotationally) to see if there is play in the shaft/bearing.
Another source of screeching is sometimes an alt bearing but that shouldn't have caused overheating.
Check that the TStat is opening.
You hadn't witnessed the engine running after checking it (except from above)?
Other options to locate noise source(s) are a hardwood dowel or metal rod or a (cheap at Horror Fright) mechanic's stethoscope.
Make sure you have oil pressure and it's not metal 'gainst metal screeching, which can overheat and otherwise ruin your day in other ways.
Hmm. Ken's suggestion of oil pressure really scares me. I was locked into something attached to the belt screeching. The way the engine was running, with these suggestions, I am now concerned about oil pressure/pump. It would explain it given the other signs/symptoms.
Yesterday, after the shut down, the next start did not stay running. The third start I shut it down quick after confirming water flow out the exhaust, with the very loud screeching.
Engine rebuild is not something I personally have time for at the moment.
WBev
What alarms did you get?
When the OP alarm switch fails, it could either way, but usually does so closed (creating a false alarm.)
To confirm, you have an M-35 NOT a 35A or 35AC?
If you have a wire off or broken then you will receive NO low-oil-pressure alarm.
That's why I added an oil pressure gauge to the panel, and maintain that CTY absolutely should have. For Pete's sake, they did not put an idiot light on the panel to indicate alternator charging.
You can troubleshoot the alarm circuit w/o running the engine.
Fingers crossed that it's something easy and not a bad oil pump !!
Ken - The engine tag reads M35. There are no letters next to it. I had a photo, but can't locate it on the cell phone anymore with all the grandson photos on there.
There were no alarms of any kind I could hear above the noise the first time it happened, and when I was at the help on start #3 there were no alarms, but I did shut it down upon confirming raw water was exiting the transom/exhaust.
Hours on engine are only 1053ish. But, given Ron and your responses, I now really suspect the oil pump. I don't believe I have tools to check on this, and if it is the oil pump, starting the engine to hear where the noise is coming from would not be a great idea as I may totally bond the pistons in the cylinders.
My plan: pull off the belt, wiggle the fresh water pump and if no movement, it is then down to internal.
I will post my findings. If my suspicion is correct, I will end up hiring a mechanic which will end my season. I had a 35 day wait to replace the PYI Dripless, etc., on my Pearson, so I bet it will be about the same.
WBev
With the key on (not running) you get no alarm?
You should get a low OP alarm. And of course a low OP alarm running if the oil pump failed.
You didn't get an overheat alarm either?
I don't know which panel or temp alrm you have. Maybe Ron can assist here --
whether your year/M35 has the added-on temperature SWITCH at the Tstat cap or if your panel has the old circuit board that triggers the temp alarm (that might have totally failed -- that's very common -- and there's no replacement.) Do you have a pic of the TStat area, or remember if you have one sender (temp gauge) or two (temp switch + temp gauge) on the cap?
WBev : Look at your thermostat housing and I believe that you should only have one sending unit which will be the temperature sending sensor. With that said, if you have a temp alarm it will be the analog to digital PC board scabbed on to the rear of the temp gage. That PC board looks like a "Dog House" in design.
Not real familiar with the early M35 engine as far as the goofy double pronged oil pressure sensor that was on the later M35 engine that was tied into the electric fuel pump.
See how many prongs are on your oil pressure sensor that is screwed in to the port side on the engine and that will tell you!!
A few thoughts
Thank you Ken and Ron. With the key turned to on, yes, there is the buzz signifying low oil pressure. Once started, the alarm seems to be off. I apologize for not stating that, as I didn't realize its' importance before. It always makes the noise and I just let it fade into the back of my brain, as a normal start procedure.
There were no other bells or whistles overheard from the noise the engine was producing.
I intend to get down to the boat this weekend. I have reached out to seven mechanics toward a rebuild price. So far, two want me to sign a work order, then they will work up an estimate. Both are reputable, but if this is common, I will have a hard time evaluating cost of rebuild versus cost of replacement.
The 35 has the good ole OP switch (like the 25, XP); the goofy wiring was introduced with the A / AC (which were exactly the same engine cept the wiring harness change and moving the OP switch away from the oil port to a bracket at the unused engine mount land.
I'd test the temp alarm. Ground the terminal on the sender - the alarm *should* sound and the gauge pin high. If no alarm the circuit board has failed.
If the alarm sounds test the sender (remove, ground the sender case with a wire/clip, put in boiling water to see if the panel alarm triggers.
You can also verify the sender by reading its resistance to ground (gauge wire removed, or sender removed.)
The resistance of the sender can be measured to determine the sender's correct operation. Remove wire to gauge. Connect an ohmmeter to terminal of sender and to engine block (or case of the sender) Approximate values are: 75°F (room temperature) = 600 to 800 ohms; 212°F = 55
Please try the water pump that is on the motor, not the fresh water pump. Try turning by hand.
Guys : Long ago I wrote a note that I had tapped the oil pressure sounder wires (a real Screamer!!) so a RED led light that I installed on the engine instrument panel also light up when there was NO Oil Pressure!! Visual and audio alarms!!
A thought :clap
Today I went back to the boat with the intent to try the fresh water circulator pump and then pull fuel to check for water (long shot). Definitely the pump. frozen and the shaft is bent, which apparently put an overload on the engine, pinned the temp gauge, and shut down the engine. The belt I put on there was an old one kept for back up. Today the engine turned freely so I believe I may have gotten away without the catastrophic failure I was told likely occurred. On the night in question, the pump did not wiggle, but I had just replaced the belt. Today I took the belt off, still no wiggle, but shot.
The oil pressure alarm does work.
So, finding a Universal pump, part 302503 is the challenge. Does any one know if the tractor part will work? Kumar Brothers USA sells one for $35ish, which might require a machine shop's help to pull and press the pulley mating surface, and one they label as proper also for the M-35 for $105 and I can have it Wednesday, for a fee. Looks like the Kubata block is V1100, and it is used in a small tractor and a small other equipment. The Universal part is $340, and I have two local places to call (Maryland Marina and Bayshore Marine in Annapolis) to see if they can get it, but I suspect a six week delay if not in stock. Maryland Marina is a fairly new authorized distributor, with few parts on the shelf. Bayshore is now part of Diversified, and I don't have much hope there.
Anyone know the answer? I also have a local Kubota tractor dealer I would go to first is a non-marinized part should be OK.
[Edited]
Had you replaced the belt before this happened or after? If before it might be too coincidental -- Maybe too tight? (can destroy both the alternator and water pump bearings.)
Quote from: WBev on September 12, 2021, 06:50:49 PM
finding a Universal pump, part 302503 is the challenge.
Challenge? Not at all -- you can order direct on the Westerbeke website. It looks to be in stock but of course, that's no guarantee.
Maryland and Bayshore are not Westerbeke distributors. Whatever they buy comes from the stocking distributor for your Westerbeke region, Western Branch Diesel.
[There are several Wb dealers in/near your area, if WBD should be able to tell you which ones show it in stock.
WBD is probably the most likely to have one on the shelf.]
Quote
Does any one know if the tractor part will work?
a non-marinized part should be OK.
There's no "**should** involved, no mystery, no hesitation.
What surprises me is how many are playing hookey from class!!! The Kubota-Universal relationship is part of every weekly syllabus!!
Everyone, memorize this.... Our engines come from Kubota with parts exactly how they are manufactured for Kb tractors, commercial/construction equipment, gensets, and for other end users. There's nothing marinized except the VERY FEW parts that Universal Oshkosh and now Westerbeke bolts on (such as the exhaust manifold and the Tstat cap) (and I'm not convinced that the TStat housing didn't come across the pond already installed.) They'll be a quiz.
Quote
a machine shop's help to pull and press the pulley mating surface
nonsense. Who is feeding you that?
Don't overthink this -- the pulley bolts on, look at the picture of the pump and your pulley.
The same pump fits the M-25, M-25XP, M-35, M-35A - the
Kubota parts manuals for those engines (they are on the Wiki) show how the pulley is attached. However, you will find that different engines and different tractors list different part numbers (most times at different prices) but they are the same part -- Kb drives you crazy with legacy part numbers that seem to change monthly.
Quote
a local Kubota tractor dealer I would go to first
Most Kb dealers NEED the part number, or the equipment (tractor) number, some cooperative ones can find parts using the Block number.
Messicks is a very good Kb dealer and supplied most of the parts manuals that I put on the Wiki.
Many owners have used Kumar parts -- as leery as I am about not using "genuine" Kubota, I haven't heard of any problems with Kumar. Depends on how comfy you feel with aftermarket parts.
WBe : I had to replace my internal water pump on my old M25XP and got the replacement (w/gasket) from the local Kubota dealer.
I believe that I had overtightened the drive belt, which caused the bearings to abnormally wear.
Now I use the Farmers Almac check. The belt is tightened so that the belt (waterpump pully to alternator pulley) can be twisted 90 degrees between your finger and thumb. Haven't had a problem sense!!
A few thoughts
Update: I found Universal parts dealers in my region devoid of parts, and Kubota not much better. Kumar did not answer their phone, and their website wouldn't take orders. Their part for the M-35 was $35 on their site. Amazon had the same for $105 + 48 for two day shipping. Part came, matched my dead one and last night I drove down to the boat and installed. I used a syringe to fill the pump chamber with Prestone water pump lube per Ron Hill, and filled the hot water heater hose, put my finger over it and guided it to the pump. Lost very little fluid. Topped of the chamber and started it up. Worked fine. No overheating, no issues.
Until, after running it for a second time at the dock at 165 degrees for 20 minutes. Pump fine. Buttoning up, doing the last search and saw my port side front engine bracket had sheared clean off where the gusset joins the flat. Might have happened any time prior as the engine was being held up by the remaining three brackets and mounts.
Searched this site, and saw a service bulletin for M25XP and M35C, from 5/1994. Well, I have a M-35. No A, B or C about it on the plate. Owners posted about their M-35A's from the same vintage as my boat. I took a shot in the dark and called Westerbeke customer service. Of course, Mr. Joe Joyce is not there anymore. I was put to Bob Massanti (phonetic) voice mail and have left a message. The lady in service, when asked what my call was about, said "your kidding." So we will see where this goes.
Toad lists what might be this part for about $800 each. C'mon, they can't be serious can they?
I'm not saying this will happen with your case but just for info, that when I first experienced an airlock (M-25) and had no clue what was going on (nor did the Catalina dealer 'diesel mechanic') the overheating occurred ONLY when pushing the engine, not running it in the slip.
As usual, thank you Ken. I appreciate your patience.
As to my test run, the first was a few minutes to confirm no leaks, in nuetral. The second was in gear after re-tightening the belt and ran in forward for 10 minutes after hitting 165 degrees. Shut down, check for leaks at the pump and hose connections. The last time,
I ran it and spent 20 minutes in forward gear at 1600 rpms with the temp gauge at 165. Of course, there was the warm up to each of run 2 & 3, but the thermostat was not open until hitting operating temp.
I have a deep slip, but am sure the prop was making a big mess in the water.
I truly hope that is load enough. I will keep the ethylene glycol anti-freeze on board just in case.
Quote from: KWKloeber on September 17, 2021, 09:48:46 AM
I'm not saying this will happen with your case but just for info, that when I first experienced an airlock (M-25) and had no clue what was going on (nor did the Catalina dealer 'diesel mechanic') the overheating occurred ONLY when pushing the engine, not running it in the slip.
I have an M25, too. When I started reading the C34 tech notes in all the back issues of Mainsheet magazine from 1987 (that my PO kindly saved and gave to me in 1998), one of the first things that caught my attention was overheating. While the text of this early tech note wasn't very helpful on the reasons for it (other than an air bubble in the line - nothing as detailed as what we've discussed and learned since, like "Burping"), it did clearly explain how to deal with it - pre-2000s solutions, was to open the petcock on the top of the engine and rev the puppy up high to spurt the air out. Yup, an inelegant solution. The reality was it worked for me for a half dozen years until we got better input and options.
This has also been discussed in great detail in a very recent thread:
https://c34.org/bbs/index.php/topic,11126.0.html
My experience, too, is if you have a serious air bubble, it doesn't matter load or no load. My engine would heat up fast even at idle. Always. Not saying other people don't have different experiences, but from an engineering point of view: air = overheat.
Like the linked thread shows, though, tiny air left means things are fine and you can do things to get rid of all the air after the big bubble is gone.
Quote from: Stu Jackson on September 17, 2021, 03:47:14 PM
Quote from: KWKloeber on September 17, 2021, 09:48:46 AM
I'm not saying this will happen with your case but just for info, that when I first experienced an airlock (M-25) and had no clue what was going on (nor did the Catalina dealer 'diesel mechanic') the overheating occurred ONLY when pushing the engine, not running it in the slip.
I have an M25, too. When I started reading the C34 tech notes in all the back issues of Mainsheet magazine from 1987 (that my PO kindly saved and gave to me in 1998), one of the first things that caught my attention was overheating. While the text of this early tech note wasn't very helpful on the reasons for it (other than an air bubble in the line - nothing as detailed as what we've discussed and learned since, like "Burping"), it did clearly explain how to deal with it - pre-2000s solutions, was to open the petcock on the top of the engine and rev the puppy up high to spurt the air out. Yup, an inelegant solution. The reality was it worked for me for a half dozen years until we got better input and options.
This has also been discussed in great detail in a very recent thread:
https://c34.org/bbs/index.php/topic,11126.0.html
My experience, too, is if you have a serious air bubble, it doesn't matter load or no load. My engine would heat up fast even at idle. Always. Not saying other people don't have different experiences, but from an engineering point of view: air = overheat.
Like the linked thread shows, though, tiny air left means things are fine and you can do things to get rid of all the air after the big bubble is gone.
The key is that the mk-I C-30 had a unique problem (that's not present on the 34) that caused an airlock and had a Rube Goldberg cooling system valve arrangement that probably led to (at least in my instance) the overheating occurring only under load. That's not ALWAYS true on the C-30 but it was at the time (right after I got her and wasn't aware of the situation. I had to figure it out thru my (re)sources (and teach the diesel mechanic) the steps to clear the airlock (which are more involved than on the C34.)
Bill : The next run you do - after hitting 165F also check your coolant recovery bottle and make sure that it is getting the extra fluid. Then after shut/cool down that the bottle level goes back to where it should be.
I said that I like to use a clear hose from the coolant outlet on the reservoir side of the engine to the bottle. That way I can see if there is a bubble or two in the line.
The line should be solid coolant.
I Keep a small jug of coolant mix onboard in case I might need to add some to the bottle.
A few thoughts
Ron:
I'll submit its better to carry separate coolant and water - then in a REAL emergency (not having water for the scotch) you're COVERED!!!
Ken : In a REAL emergency you can use just water lube!!! I'd also add some water pump lube to it!!
A thought
Just don't use the scotch in motor!! Terrible waste of scotch.
I question in a REAL emergency who'd want water pump lube in their scotch?
Who wastes water in Scotch?!? Arrgh... :shock:
I had the same bracket failure problem on my M25xp and Joe Joyce sent me replacements.
While waiting for the replacements, I had one of the broken ones welded back together, at least for a backup. The new bracket had a longer gusset plate, to prevent the bracket from failing again. So far so good.
Going to meet the welder in ten minutes. I had ordered the new brackets Friday, and, like Roland, hope to get this one welded as a "spare" with a longer gusset installed. I read the wiki on replacing motor mounts, and the comments, as well as many of the posts about doing so. I hope to not have to raise the engine much, if at all, to remove and replace the bracket.
Currently the new brackets are out of stock, but remain in production. So the weld fix, if it works, may have to stay a while. My port-front mount looks good, but I will check it out today assuming I can get the bracket off. Good weather, so hoping for the best.
On the overheating issue, there is no overflow tank on the boat. I will have to look into one. The Universal installation manual says the engine came with one.
Thank you all. I will post anything interesting I encounter.
Bill : I (and you can) made a coolant recovery system for the cost of a 1qt "Rubbermaid" bottle and a couple of feet of 3/8"?? clear plastic tubing. Then figure out where you can mount the bottle (I wrote a Mainsheet Article - early 1990s). You need to be able to see the bottle (check the coolant level) and maybe add a bit of fluid maybe once a year.
The bottle should be about the height of the engine and doesn't necessarily need to flow out the bottom of the bottle. Probably a far cry from the Westerbeke bottle cost!!!
A few thoughts
Quote from: Ron Hill on September 19, 2021, 11:12:25 AM
..............
....................
......................
(I wrote a Mainsheet Article - early 1990s).
......................
..................
...................
In tech notes, need to be an IA member to access:
https://www.c34.org/mainsheet/pdf/2000_no2.pdf
Quote from: WBev on September 19, 2021, 06:48:53 AM
there is no overflow tank on the boat. I will have to look into one. The Universal installation manual says the engine came with one.
WBev
Many don't understand the differences between engine-manufacturer supplied and/or installed and boat manufacturer installed. The Universal manuals don't always equal what Catalina decided (or not) to install. Sometimes, even if it's shown as part of the engine, the boat manufacturer might not have purchased it to install.
Just one example: The Universal manuals show a harness schematic with certain color coding. One might think
That's part of the engine and is on my boat. Not so -- the coding/schematic is for UNIVERSAL's harness. Catalina fabricated its own and the color-coding often doesn't match the Universal schematic. It sometimes seems like they used whatever wire they had hanging around. I mean, how difficult is it to continue on with the same color wire? Really.
Owners often lament about an engine issue (blame Universal) when it's actually a Catalina's whoops. And sometimes blame Catalina for what actually was a Universal screw-up (e.g., the 2" heat exchanger.)
Sometimes it's a perfect storm (e.g., Universal's harness/gummy bear plugs coupled with Catalina's ammeter on the panel.)
My point: just because a manual says "
it's there" doesn't mean "
it's there." Heck, one Universal manual describes the
radiator that's on our boats.
I guess Catalina forgot to install that. :shock:
A universal (small u) Dorman coolant recovery tank can be had from Autozone for <$9 to <$19 depending on the type and mount.
Ken, thank you. I will be checking out the local auto parts stores and seeing where I can mount the tank. Your advice is spot on with what the boat builder does versus the engine builder/supplier, or any other sub part provider.
As of today, my two day shipping water pump has taken over 10 days to get here. The Kumar Bros pump is squealing a little. I loosened the belt and reduced the squeal. I will have to do so again it seems.
Bill
PERFECT Bill. Good luck on the water pump replace. If you have any tips during, grab the cell phone camera.
Oh, Kumar didn't tell you it's 2-day shopping OUT of India - the remainder is pot luck? LOL :rolling :rolling
Bill : As I said, the tank should be about the same height as the overflow outlet just below the pressure cap!! It doesn't need to feed from the bottom.!!! Look at my Mainsheet tech note article where I used a 1 qt Rubber Maid bottle. A hell of a lot cheaper that the Westerbeke jug!!! :thumb:
A few thoughts
Ron - I read it. Real question is where on the wall I will put it, whether Rubbermaid or Autozone. I will figure it out. Right now the overflow hose goes to the diaper.
Quote from: WBev on September 24, 2021, 03:23:11 PM
Ron - I read it. Real question is where on the wall I will put it, whether Rubbermaid or Autozone. I will figure it out. Right now the overflow hose goes to the diaper.
I think Noah added a reservoir "recently" and had a pic, maybe it will show up here.
Bill : How about around the corner in the lower aft cabin???!!!
A thought
Nope: i do have a coolant recovery tank but it was on my boat when I bought it. The "other stuff" is my glow plug solenoid...(successful foe me, but controversial for some). :abd:
Bill here's some other pix in this thread, and repeats Noah's (apologies for my CRS.)
https://c34.org/bbs/index.php?topic=9551.0
I am posting on this topic because yesterday after motoring for about 90 minutes my temp gauge showed sudden overheating (240). Curiously the overheat alarm did not ever sound. I did not check water flow from exhaust, but then cleaned the sea strainer and changed the impeller. Water flow from exhaust thereafter was normal, but temp gauge continue to show overheating so I got a tow back to the marina.
Today I confirmed all connections good on the back of the temp gauge and on the sending unit. I then found a wire disconnected from the thermostat cover. I don't know what this wire is for but thought I had solved the problem. No such luck. After starting the engine and running for 15 to 20 minutes the gauge again rose to 240°. I checked the external engine temperature with an infrared thermometer, as suggested in an earlier post, at a thermostat cover & on the engine block & near the radiator cap with an infrared thermometer and got readings up between 150-160, so something is screwy with the temp gauge.
Randy
Post a pic of your TStat cap and wire.
There's Teleflex gauge troubleshooting instructions that I posted on the Wiki that gives you the steps for checking that.
It could be a bad gauge, a bad sender, or a bad circuit.
Since it's more easily got get to, test it out using the sender wire to see how the gauge reacts, then test at the gauge itself if the first round doesn't reveal the cause. Then last you can test the sender resistance in room temp and hot water or replace it (about 25 b.)
Ken:
I tried posting a pic of the thermostat wire connection from iPhone but it errored out saying file too large. How do I post a pic from iPhone photos?
Randy—An easy way with an iPhone photo is to email it to yourself. It will ask you to select a size. Select a reduced size from choice (up to 500), then download it from your email back to you photos. Then use that "new sized" image to upload to the site.
Randy
The one at Sailor's 6 o'clock is the temp gauge sender.
The one at sailor's 2 o'clock is the high temp alarm switch.
Disconnect the gauge S wire and the gauge *should* pin low.
Ground the gauge S wire and the gauge *should* pin high.
If that doesn't happen then pull the panel and check the gauge the same way.
You have the convoluted B engine wiring scheme that can screw up the temp alarm. If you ground the temp switch S wire the alarm *should* sound.
Let us know....
Today I did Ken's suggested tests.
From the sender @ the thermostat cover I disconnected the S wire, turned the key on, and the temp gauge pin was high, not low as expected. Then I grounded the S wire and the temp gauge continue to pin high. I assume this does not confirm the sender is OK, but confirms there is a problem from the sender wire at the thermostat through to the temp gauge.
Next I opened the instrument panel, disconnected the S wire from the back of the temp gauge, turned the key on and the gauge pinned low as expected. Then I put a jumper on the back of the temp gauge from the S terminal to the ground terminal and the gauge pinned high as expected. I assume this confirms the temp gauge is working correctly.
It appears the problem is likely not the sender or the temp gauge, but most likely the wiring from the sender to the temp gauge. Is this correct? Where to next?
Randy
Good eye. Your observation/conclusion is correct (caveat:this is w/o being hands on there.)
I would verify the further by:
1) Verifying whether you have a good ground at the temp sender. Either with a meter or grounding the sender case to a good negative. But I think you probably grounded the S wire to a good known negative so that kinda eliminates that possible cause.
2) Before I tore into the harness I would run a long wire if you have something around (w/ alligator clips?) to the cockpit to bypass the S wire. That will for sure nail down whether it's the S wire being bad.
The gauge pinned high, if it's the S wire, means it's grounded (insulation off, pinched somewhere maybe) and 'permanently' telling the gauge that the sender has zero resistance (overheating.)
You could also check the resistance between the sender case and terminal. If it's zero or very low (with a cool engine) then there's something wrong w/ the sender. The troubleshooting guide lists some normal resistances at different temps. The relationship is not precise be aware, temp gauge can vary 15 deg or so, so resistance is just a guide.
I like the idea of running a long wire directly from the sender to the gauge and bypassing everything else. I'll give it a try in the next day or two and let you know what I find. Thanks for the suggestion.
Randy : Make sure that you have a "rubber" protective boot over the connection on thermostat. Any contact with the metallic insulation will screw up readings!!
A thought
Today I ran a wire with alligator clips on the ends from the sender (@ thermostat) to the S terminal on the temp gauge. The gauge worked perfectly and did not show overheating or deviate with changes in engine rpm or extended runtime. This confirms it is the yellow circuit/wiring from the sender to the gauge. Now I need to find where the wire is cut, pinched, corroded, or otherwise bad connection.
The most likely problem seemed to be a bad looking ring connector at the sender. After reconnecting the original wiring I changed the ring connector but the temp gauge problems continued. The most likely problem areas now seem to be end terminals, wire joints/connections, plug connectors, or tight turns.
So how should I go about finding the fault in the wiring?
Does anyone know wire routing once it goes down in front of the engine and behind the alternator?
Where in the aft cabin does the harness run?
Is the a plug or other type wire connection between the engine and where it enters the SS pedestal tube?
Thanks for your ideas and suggestions.
Ron: There was and is no protective rubber boot at the sender. What does this look like and where do I get one?
Randy : You are probably better off just running a new wire all the way, rather than trying to spend time looking for a break!!
The RED rubber boots are a 90 degree cover that slides on the wire so it also covers the terminal connection. look in the electrical section of a marine chancellery.
A few thoughts
[edited]
Randy
The BC temp sender being on the butt end of the TStat cap might not be issue as far as shorting out but still, it will never hurt.... You want a Blue Sea # 4008 boot, WorstMarine, Defender, etc.
You did check it with the engine cover off [no insulation interfering]?
The Universal B engines sported a black RV plug on the harness (if you look at the cut sheet for the M25XPB on the WIKI you can see it. I presume that CTY kept the switch [RV plug] in place. Sorry, I can't link you to it cuz I haven't had access to the wiki for like 6 months. See WIKI > MANUALS
The schematic for the BC engines is also on the Wiki WIKI > MANUALS.
Again, if the gauge is pinned high then the S wire is permanently grounded somewhere, not a "bad connection" (i.e., high resistance or open circuit, which would pin the gauge low.)
The terminal on the high-temp switch is THE WORST for on a boat. They make a switch that has a 1/4" quick disconnect terminal (which is only one step above -- I haven't found a screw terminal switch yet.)
Today I solved the riddle of the faulty circuit. The temp gauge is now functioning properly. I planned to run a portion of a new wire from the sender to the temp gauge and started by opening up the harness in the aft berth, separating the yellow (temp gauge) wire from the others and then cutting it. I used a jumper wire with alligator clips to determine the problem was from that point forward to the sender, and that everything from that point aft to the temp gauge was ok. Before beginning the process of routing a new wire around and under the engine, I cut additional wire from the sender terminal and replaced the heat shrink ring connector again. Viola, that did the trick and the temp gauge is now behaving normally. Evidently the unprotected wire had been bent and compromised too many times so cutting it back further did the trick. I've ordered a Blue Sea #4008 boot from WM and will install it for added protection when it arrives.
Thanks Ken and Ron for your responses and assistance.
Quote from: Rortega46 on October 13, 2021, 07:26:40 PM
I cut additional wire from the sender terminal and replaced the heat shrink ring connector again. Viola, that did the trick and the temp gauge is now behaving normally. Evidently the unprotected wire had been bent and compromised too many times so cutting it back further did the trick.
Randy
That's great that she's working now, BUT the cause (broken wire near the ring terminal) makes no sense.
Quote direct from the gauge troubleshooting:
3. If sender is
shorted (0 ohms)
gauge will read above 240°F. (
Your gauge symptom)
4. If sender has infinite resistance (
Open) gauge will read
below 120°F. (
Your sender wire condition.)
Oh well, it's a boat.
Comment -- your wire condition is why it's important to tie down any wire within 6" of a terminal (ABYC).
Flex can destroy a perfectly good terminal connection. I usually add a pc of heat shrink on the terminal/wire to act as a strain relief where there may be some flex. Also, because the 14 ga (BLUE) terminals are not as hefty as the 10-12 ga (YELLOW) terminals, I use the yellow ones on engine connections (skin back the copper 2x long, fold over and crimp it doubled-up in the 10-12 gauge terminal.)
Ken, I think I understand what you're saying in that I may have fixed the problem but it may recur because I didn't get to the source of the problem.
I believe the problem is in the first 6-8" of the yellow sender wire since it is unprotected there and repositioning it after cutting an inch or so seemed to fix the problem. Wherever was grounding the circuit was likely moved enough to eliminate the short. For now I will put a boot around the connector and split loom on the exposed wire as far as I can. I will also keep a handy dandy laser thermometer on board, so if the temp gauge shows overheating, I can check engine temp at the engine block.
Randy
"Sort of but not really" what I'm saying.
When you say unprotected, I presume you do NOT mean no insulation on the yellow wire.
The way that the gauge would pin high (if it's a wire issue) would be where there is no insulation (worn, burnt, wire broken and sitting against a ground) and there is a dead short to a ground (ie, the same condition as when you grounded the S terminal on the back of the gauge.). What you're describing is the polar opposite of what **should** have happened. My mind is blown about the cause/symptom/fix/result. It just does not compute (but after all it is a boat.)
Could the sender terminal have been grounded to the engine compartment insulation when you did the testing?
PS, what kind of seawater temps do you run (high end)?
Ken
When I say unprotected I now understand this to mean no insulation on the yellow wire (worn, burnt, wire broken and sitting against a ground).
I can't explain why it's working now and don't think it's the new terminal connection. I suspect it's somewhere along the first ~10" of the sender wire which was likely previously grounded but no longer is because it has been shortened and moved. I can't prove it because the exact reason/spot of the grounding has not been isolated.
I don't think the sender terminal was grounded to the engine compartment insulation when I did the testing. Seawater items lately have been ~ 74°.
I have a similar issue on a mkII with a Universal M35B Engine.
I've recently replaced the temp sender with a new one from Catalina Direct, when that didn't fix the problem (gauage stating the temp was >240'), I found and read through this thread.
Today I ran a new S wire direct from the new sender to the gauge and the gauge still showed >240'F.
A couple of other points. With the S wire disconnected, the gauge pins low. As soon as the gauge is reconnected with a warm engine the gauge pins hot. When starting from cold, that gauge reads low, but quickly shows increasing temperature until it is pinned hot.
Looking at the new sender I realized that I used teflon tape to ensure no leaks at the thermostat, so I removed it, wire brushed it, reinstalled it and still the gauge reads <240'F. Am I correct that if the sender isn't grounding to the engine (teflon tape), I would get a high temp reading?
This is the classic "fix" of what I call "parts whack-a-mole." Instead of proper strobleshooting — replace this part, then that part, then the other thingamajig.
The Teleflex troubleshooting guide is on the techwiki, is easy to follow, and very quickly allows one to determine whether it's the gauge, S wire, panel ground, etc. It even gives the temp and resistance values to use to check if the gauge sender is at least anywhere in range.
" With the S wire disconnected, the gauge pins low.
When starting from cold, that gauge reads low, but quickly shows increasing temperature until it is pinned hot."
Are not the proper troubleshooting steps. Follow the steps in the guide.
Check the gauge at the panel
Check the S circuit back to the gauge
Check the sender.
Verify a bad component.
Guys : Teflon tape is great for plumbing connections NOT for electrical connections. If you have one wire coming off a sender/switch the threads are the other connection!! Live and learn!! :shock:
A few thoughts