Ignition Power Universal M35

[Ron Hill]

Ken : "Ron, what do you mean by "straightened out"?  Are you saying that the 35BC doesn't have the convoluted fuel pump/alarm/oil switch wiring?"

Sorry I didn't go into great detail in my statement "straighten out".  In the Mk II C34 Catalina, did not send the output from the alternator to the key switch (volt meter) and then back to the batteries"  which was one of the problems with the original MK I wiring harness. 
The M35 BC engine still has that goofy fuel pump/alarm/oil switch wiring!!

A few thoughts

[KWKloeber]

@Ron.  Ahhh ok, I hadn't even thought about the ammeter deal.  A lot of peeps blame CTY for things Universal did and blame Universal for CTY/Seaward quirks.  Westerbeke actually stopped sending alt power thru the RV plugs after it bought Universal Medalist and converted the harnesses (with the introduction of the "A" engines (25XPA, 35A, etc., series)) to its "W" engine standard (e.g., W-30, W-33.)   eg, "A" designates only a wiring change, as we know "B" designates a completely different engine with the same wiring as the "A."  T.M.I.

@Mark_S

It's my quirk when troubleshooting that I do not like fiddling with things -- and a problem "going away" and not knowing whether I actually fixed it or a coincidence made a symptom disappear.  When I am able, I much prefer systematically narrowing down what caused the symptom and then fixing only that and moving on to the next -- so that I know exactly what to expect down the road.  So what I mean is IIWMB, it'd first investigate WHY at rest there is a ~2v difference between the battery and key switch -- which might point to the cause of losing power at the panel.  (Again IIWMB,) I'd replicate the symptom and systematically look at each V point from the key switch back to the battery to see where the V jumps back to battery voltage. 

RE: Alt - Depending on whether the mechanic changed any wiring, the +12v Alt field excite is driven from the key switch (but runs first to the oil pressure switch) so if there's a problem along that route it could affect the Alt output -- the harness at the oil switch location is notorious for problems (a terminal can break off because Wb used stiff untinned SAE wire instead of flexible tinned marine wire. and vibration gets transmitted to the oil switch terminals.)

RE: low V at the key -- there could be something drawing down the V, not necessarily a bad terminal/lug connection  The V at the preheat solenoid would be key because it comes straight from the battery cable (from where it's connected to the starter solenoid B terminal.)

I attached the schematic for the B(C) engines. The 10a circuit breaker at the preheat solenoid is also problematic - it gets corroded and fails (which affects the oil pressure/alarm circuit.)

Another hint to look for - very often panel power issues are due to a bad "ground" (negative) somewhere - either at the panel or where the harness negative wire is grounded (I don't know where that occurs on the B engines.)

[Mark Stein]

Hello Again from Milwaukee.

Stu wisely advised me to start my discovery process with a good cleaning of the battery terminals.  After that was completed, it now seems fine.  It would be interesting to know how many of us unsuspecting newbies (not new to the boat, just the complexities of marine electrical systems) have admitted embarrassingly, that it was a simple solution to a confusing problem.  I have to add my name to the list - again...  Thanks to you all for the guidance and insights again.  The experience taught not only considerably more information than I had previously and was somewhat hesitant to learn, but also a valuable lesson in keeping that battery compartment on the checklist of high priority maintenance issues.

Other lessons learned were to keep those engine electrical connections clean which will be happening next.

Incidentally, the SteinWay IV has a Universal M35AC engine. (I uploaded a photo of the plate on the engine but file size was too large - sorry).

Ken, my X country was in a 152 (along with 75% of my training).  I now only rent the 172s but haven't flown since October.

My thanks to you all and if I could, I'd stop by each of your boats with a cold six-pack.  You guys are the best and C34 owners are fortunate to have such an important resource.  Enjoy your summer and good winds and flat seas to you all.

-Mark

[Mark Stein]

Hello Ken,

Just saw your last post this morning after I posted my fix and thanks for the diagram which is much better than my owner's manual.  Is this different from the M35AC model?

Thanks!

-Mark

[KWKloeber]

Mark which manual do you mean?  Catalina C34 manual or Universal engine manual (date, rev #?)? 

The short answer is that the #200360 wiring schematic is good for both the M-35A(C) and M-35B(C) but not for the M-35.

The diagram and schematic are in the engine Ops Manual and Service Manual  -- when Westerbeke bought Universal "all" it did was revise the wiring of the older engine models (m-25XP, M-35, etc.,) use a different oil pressure switch (moved off engine block to a remote location,) and install the breaker and preheat solenoid arrangement (to confirm to the same scheme that Westerbeke previously used.) 

The M35A(C) engine itself is the same as the M35.  The "B" series engines (eg, M-35B(C)) are different engines than the "A" engines, but the "As" "Bs" both have the same convoluted wiring scheme.   "(C)" merely designates it's wired to CTY's spec and engine panel, not Westerbeke's panel (the alarm and some other things are different between the two.)

[Stu Jackson]

Just a Heads Up

Whenever I see reference made to the "#200360 wiring schematic" my ears perk up.  Back in 2007, we had an extensive and long discussion about that (those?) wiring diagrams.  Because I have a strange memory for numbers, that one has always stuck with me.  I was on vacation back then from San Francisco to here in British Columbia, and thus had time to spend on Michael's issue.  I researched the referenced two "#200360 wiring" diagrams and determined and described why they were different.  While one is a physical wiring diagram and the other is an electrical schematic, the point is the wiring is different. They both have the same number and appear in consecutive pages in the M35 engine manual.  They were not for my engine but I got into the details for that topic.  I do not know if they (the diagrams) have been corrected (the wiring differences between two identically numbered diagrams) in past eight years.

My purpose in sharing these links and excerpts, which are prominent in the Critical Upgrades topic, is to simply point out to those who choose to investigate these wiring diagrams for their boats that here is a potential issue they should understand and resolve.  I do not know if the differences between the diagrams have been corrected to agree with each other in the past eight years.

Please also note that since I contributed to this eight years ago, I have no further interest in delving any further into the differences between "the M-35A(C) and M-35B(C) and the M-35."   I'll leave that up to those of you who own those engines.  And thanks to Ken for describing the differences so well.

Your engine, your choice. 

* * * * * * * * * * * * * * * * * * * *


Reply #30 --- Page 3 of Critical Upgrades includes this:

In 2007 we had discussed this in a very looong thread:  Hard Starting/ Possible glow plug problem?? M35 Engines & Fuel Pump Wiring

http://c34.org/bbs/index.php/topic,3347.45.html

Reply #52 on page 4 of that topic begins to discuss the wiring to the fuel pump, how it works, issues with bleeding, and continues to end up describing exactly the issue that Dave addressed in his question.

These are two excerpts from that referenced link:

Post #49 ---

The manual I was using is the one on this website, http://www.c34ia.org/manuals/Operators-Manual-2of2.pdf .  The same wiring diagram 200360 is on page 25 and schematic 200360 is on page 26 (pages 5 and 6 of the pdf). 

[Updated by Stu 10/22/2020]
That link has been superseded by this one:  http://c34.org/wiki/images/1/19/Universal_A%28C%29_series_engines_%28M-25XPA%28C%29%2C_M-35A%28C%29%29_operators_manual_OCR.pdf
Look for pages 25 & 26 of the manual, NOT the PDF pages.


Post #52 ---  My reply

Grounding & Wiring Diagrams:  Continuing with comments on your # 37:  Grounding should have nothing to do with your "issue."  It appears that it is one of significant differences between the two quoted Catalina wiring diagrams, and a POSITIVE-side  power issue, unless, of course, your grounds aren't solid.  You wrote: "Now the problem as it is theorized to be is that because the electrical circuit ("preheat solenoid activating circuit") that energizes the preheat solenoid (which acts as a switch to close the glow plugs circuit) runs through the electric lift fuel pump (a clever way to make sure that when the glow plugs are energizing fuel is also being delivered by the lift pump to the fuel injection pump for onward delivery to the cylinders when the engine cranks), if the lift pump electronics are making and breaking they make and break the preheat solenoid activating circuit with the result that the preheat solenoid does not close - or closes intermittently..."  What's so "clever?"  If the pump was ON from the ignition switch, it wouldn't need to be connected to the solenoid at all, and there wouldn't have to be two wires to the pump.  And, it is entirely useless to have the pump running before the engine starts, so why have it "linked" to the glow plugs at all?  Although "our" design does have it run then anyway, right?   Following your logic would mean that the lift pump is OFF just when you need it: when the engine starts!!  Think about it.  And, based on the wiring diagrams noted in your later post # 47, that simply does NOT seem to be the case.    The power to the solenoid simply is NOT  shown on either diagram to "run through" the fuel pump: the circuit goes FROM the keyswitch TO the solenoid and then TO the fuel pump.  The fuel pump has two feeds on the page 25 diagram:  one from the solenoid when the keyswitch is being held to energize the glow plugs via the "S" terminal of the keyswitch, and second, from the "I" terminal of the keyswitch when the engine starts and the oil switch closes.  On the page 26 diagram, the glow plugs and the fuel pump are in PARALLEL, on both pages 25 & 26 the fuel pump and oil pressure switch are in SERIES.  BECAUSE the fuel pump is in SERIES with the oil pressure switch, the pump will NOT run until the engine starts unless it is wired with the double inputs on page 25.  On that page 25, the pump WILL run when the glow plugs (solenoid) is held ON with the "S" spring on the keyswitch. You are correct in your summary, but my point is that the wiring just doesn't go THROUGH the fuel pump to the solenoid, it runs FROM the solenoid TO the pump when the keyswitch is held on.  It's a subtle, but important difference, because I see no way that your theory that the pump is affecting the glow plugs should apply.  You can easily TEST my understanding of the circuits:  either disconnect the fuel pump or close the circuit breaker, if there is one, from the solenoid to the pump. 

Wiring Diagram Discrepancies: These are TWO serious discrepancies between the two wiring diagrams. (1) Circuit breakers:  Page 25 of the wiring diagram shows the circuit breaker downstream of the solenoid TO the pump.  Page 26 shows a circuit breaker between the oil pressure switch and the resistor to ground.   (2) Connections to the pump from the Positive (+) Wiring Side:  Page 25 shows the wiring from the downstream side of the solenoid to the + side of the fuel pump, while page 26 shows the wiring from the end run of the glow plugs to the (-) side of the pump.   They are numbered the same (#200360) but they are very different re: the pump operation.  On the page 26 drawing the pump simply should not start from anything BUT the oil pressure switch. Follow both the positive wiring TO the pump and the grounds from and around it.   You need to find out what you have on YOUR boat before you go adding stuff.  I would find that out first if it was my boat.

[KWKloeber]

Just a Heads Up

that here is a potential issue they should understand and resolve.  I do not know if they have been corrected in past eight years.

200360 diagram and schematic:

There's nothing to be "corrected," the Schematic and the Diagram are functionally identical.  The pages in the engine manuals are an adaptation of Westerbeke engineering drawing #200390 (attached,) which was a revision to engineering drawing #39144 (which is the "Westerbeke" standard.)  The left side (of both drawings) is the "Diagram" and to the right is the "Schematic." The left side of both drawings is electrically identical to the right side, and in the engine manuals the "Diagram" is electrically identical to the "Schematic."

I think? I had posted about this back in June 2018 after I traced out each wire/circuit/connection point and component between the two drawings and found them "electrically equivalent."  However, the schematic is poorly drawn which adds confusion (the Diagram better depicts each physical wire and physical connection point/component.)  Other than the bad artistic depiction they operate the same "electrically."

[KWKloeber]

Maybe I can put to bed that the apparent discrepancies are not discrepancies (I wish that I could go back in time so that the confusion doesn't live on):

Wiring Diagram Discrepancies: These are TWO serious discrepancies between the two wiring diagrams.

(1) Circuit breakers:  Page 25 of the wiring diagram shows the circuit breaker downstream of the solenoid TO the pump.  Page 26 shows a circuit breaker between the oil pressure switch and the resistor to ground.

Using several colors to deconfuse things, ATT 1 shows that they are identical -- 

Both 25 & 26 show that +12v power (blue) feeds one side of the 10a circuit breaker and the other side of the breaker goes to both the lift pump (green) and thru the 1K resistor to ground (red.)

(2) Connections to the pump from the Positive (+) Wiring Side:  Page 25 shows the wiring from the downstream side of the solenoid to the + side of the fuel pump, while page 26 shows the wiring from the end run of the glow plugs to the (-) side of the pump.   

On both 25 & 26, the  -12v side of the pump (black) and -12v side of the glow plugs (black) connect to engine ground (black.)  Both also show the +12v side of the pump powered (green) thru the preheat solenoid (I terminal) and the glow plugs fed (orange) from the power post of the solenoid.

Both also show the lift pump alternately powered from the oil switch (purple) when there is oil pressure.


THERE IS an error in the Schematic (how the glow plugs are depicted looks to be in series.)  In actuality, the +12v and -12v should connect to the individual depiction of each glow plug (they are powered wired in parallel, not on plug to the next.)