Engine Wiring Harness Ideas from Ken

[KWKloeber]

One more comment, which is a bit of a restatement from jon above.   Check the critical upgrades.  In my mind, for my year boat, there are three key ones, the traveler through bolts, the alternator bracket and the wiring harness.  My PO only did one of the 3 on a 86 boat.  It tells me that he might not have been kewping up an evwrything else.  You are doing the right thing to learn about the boat in advance to see what you should look for.

I would add to the wiring harness (not covered in the past) is that the typical harness fix does not address a a couple serious shortcomings on the M-25/M-25XP engines.  There is no over-current protection on the power lead to the panel.  Also the fix does nothing to replace the non-marine grade wiring from the gummy bear plugs to the engine/alt. etc.  and the non-marine grade terminals.

Owners should:

1) Eliminate the in-line fuse on the "S" wire to the starter solenoid - it's at the wrong end of the harness and is useless.
2) Place an in-line 10-awg ATC fuse holder on the red power lead that runs from the solenoid "B" post to the cockpit panel.  You propbably need a 30-amp ATC if you don't have the engine glow plug relay modification.  But use the lowest amperage fuse that doesn't blow while cranking the engine with the blower running and glow plugs energized.
3) replace wiring (or at least the terminal ends) on the engine side of the removed Gummy Bear plug)

#2

The european terminal strip "fix" that Catalina Direct and Seaward pushes is probably the worst idea, second only to leaving the gummy bear plugs in place.  The 'fix' is non ABYC compliant and leaves many issues remaining with the terminal strip itself, and that it doesn't address the prime issues with the harness itself.  If someone is going to spend the time and money to address the harness issues, do it correctly and so it's ABYC compliant and not a problem waiting to happen again.

yes, I am highly opinionated about this issue because it is sore spot that Universal. CTY, Seaward, and CD have created and refuse to recognize that there are fatal flaws in the harness, and instead downplay that by pushing a "simple fix" that really doesn't recognize and address the flaws.

Ken K

#3

From waterdog

Ken can you remind us of the facts?   What is it about the harness that makes it non compliant?   Is there too much current for the wire size?   Are the terminal strips the wrong type?   Is there too much current for the terminal strip connectors?   Corrosion vulnerability in the particular location?   Does ABYC call for no connections between the engine and the panel? Is it running the start load to the panel and back?

It is clear that you don't like the original harness, and you don't like the fix.   I would like to understand the root of your displeasure.   I have a new Beta engine with a connectorized harness.    I would like to understand if there are related issues and what the specific concerns are.

Thanks,

Steve

#4

Ken can you remind us of the facts?   Thanks,

Steve

Steve,

I have wanted to put together (and Stu and I talked about) a complete primer on the harness, panel connections, issues, etc, but I just haven't had time to get 'er done.  Thanks, this is is a good shove.

Stu, I'm going to answer this in pieces, trying to remain on target/topic in each post.  I can tweak all the text later to massage it into a wiki.


This isn't a complete and totally logical presentation, but for your immediate needs should begin to answer your questions.  I need to put together a Tech Wiki article and hope this is the beginning of it.  Editing/proofreading is not at 100%


For the OEM harness:

First, to be clear we're talking about M25 and XP, XPA engines/harnesses and not harnesses on B-series engines.

The harness has these bi-directional functions [Insert a flow diagram to illustrate this]:

To deliver TO THE PANEL:

1) "Full" battery voltage/high current from the positive battery post, via the battery selector switch, battery cables, and the solenoid "B" post, to the cockpit panel (Harness Wire #5, red.)

2) A (solid, clean, interrupted) alternating current pulse signal from the alternator to the tachometer. 
This DOES NOT go thru the gummy bear plugs for obvious reasons (HW#10, color varies- orange, brown.)

At the panel, power is DISTRIBUTED TO the:

3) Blower, when the panel switch is on.

4) Gauges, alarms, and gauge & panel lamps, when the key switch is on.

IN THE OPPOSITE DIRECTION (back from the panel), THE HARNESS provides:

5) Voltage/current BACK TO the starter solenoid, when you operate the key switch and/or starter button (depending on panel model) (HW#3, color varies - yellow w/red, white, solid yellow.)

6) Voltage/current BACK TO the glow plugs, when you operate the preheat switch. 
If you have the glow plug solenoid/relay modification, it delivers voltage/current BACK TO that relay or solenoid that was added in the engine compartment. (HW#2, usually gray.)

7) The ground path BACK TO the neg battery post, via the grounded engine block and neg battery cable, to operate the blower, gauges, and gauge and panel lamps, and alarms.  That's all -- it has nothing to do with starting, your alternator, glow plugs, etc. (HW#!, black.)

8 ) The path from the panel alarm BACK TO the oil pressure switch (HW#7, light blue) and coolant temperature switch (HW#9, tan if you have one.)
These are "normally-open" switches that activate those alarms when the switches close (oil pressure goes low or temp goes high) to complete the alarm circuit path back to the neg battery post via the grounded engine block and negative battery cable.

9) The path from the panel gauges BACK TO the coolant temperature gauge sender (HW#8, brown and fuel tank level sender (black, not on the engine harness schematic and doesn't go thru the gummy bear plugs.) 
On a tangent here, NOTE the misnomer. These are called engine "senders" but they send no signal or anything else TO the gauges -- they RECEIVE current coming BACK FROM the gauges.  The "senders" are variable resistors that "throttle" the amount of current they allow to return back to the neg battery post (via the grounded engine block and negative battery cable.) 

So, a "sender" (e.g., temp sender) is typically a varying resistor and a "switch" (e.g., high temp switch) is simply on or off.

10) Voltage/(low) current BACK TO the alternator to excite the field so it begins producing charging current (HW#6, usually purple.)

11) Voltage/(low) current BACK TO the fuel lift pump (HW#9, sometimes red, sometimes black) This DOES NOT go thru the gummy bear plug.

We all should agree that the gummy bear plugs are a problem (the hard white plug on the engine side is OEM Universal and is marginally better than the mating gummy bear plug.) 
Universal supplied M-25 and XP/XPA engines with that white, 8-position, "trailer" plug on its engine component wiring that it added to the Kubota tractor engines.  But if they're so bad why are they there? (on new engines Westerbeke/Universal still installs similar plugs.)

Since the engines came with a plug, CTY had to decide whether to:

a) Pay Universal for it's mating harness. NOT ($$)
(Universal's harness didn't exactly match the configuration of CTY's/Seaward's panels/instrumentation.)

b) Buy both the Universal harness AND Universal's cockpit panel. NOT ($$$$)

c) Cut off Universal's plug and hard wire the harness extension to the cockpit to the engine pigtails
(this would have added about 15 minutes time per install and reduced material cost (no special harness with fabricated gummy bear plugs would be necessary.)

d) Remove Universal's wiring and fabricate/connect it's own harness to the engine (very time consuming,)

or unfortunately, what CTY/Seaward did do,

e) - Fabricate their own harness with a plug to mate to Universal's plug.

So they moulded the softer, brown gummy bear plugs onto the harness wires.  Additionally, instead of hard wiring the cockpit panel they unfortunately put another gummy bear plug hidden behind the panel.  But if they didn't, CTY techs would have to had completed the wiring to the back of the panel, gauges, etc. (chance for errors) on the panels that came from Seaward -- this way the techs just plugged in the panels and screwed them home.
   
These two sets of plugs were obviously installed without realizing the initial downside of having plugs, or the potential implications for years to come thru the line of who knows how many owners.  It's a prime example of needing to, when it comes to marine installations, totally over-bullet proof products/materials, instead of doing only what is adequate for ideal "factory floor" conditions.

When I was young/dumb (before these great forums) she was my first "real" boat (w/ one prior owner for 9 years) -- and I sorted out potential problem areas.  I thought, "What the hell - clean up those plugs, squeeze the connectors tight to make good contact, tape them up to prevent corrosion -- and I'm good to go."   

Fast forward two decades -- here's the engine gummy bear plug after unwrapping the tape during some whole-boat wiring upgrades. 

[attachimg=#]

So, engine heat destroys the plugs, but that's not the whole story.  There shouldn't be high current going thru that type of bullet connector TO the cockpit panel and then BACK to the starter solenoid, glow plugs, and BOTH ways ESPECIALLY for the alternator charging circuit (which could be a much higher current.)  Couple all that with potential corrosion on the plugs, and you have a real problem with (at best) poor or no starting, incomplete battery charging, gauge reading problems -- and at worst, plugs overheating, melting, and a fire hazard.

Thank heavens I had tape-wrapped my plug, or I certainly would have had a short and fire at some time. 
For those who don't care to ELIMINATE the gummy bear plugs - Your boat, Your choice, but unfortunately they might take your dock neighbors' boat along with yours.



For the wiring harness itself - there were different versions but the basic issues are:

1. No over current protection on the power feed to the panel.  Per ABYC there must be a fuse within 7" of the solenoid "B" post.

2. The barrel fuse near the "S" terminal on the starter solenoid is useless, problematic (corrosion), and should be REMOVED -- and NOT replaced with another style fuse holder.  What does it protect?  I know why Universal put it there -- in case the quick-connect terminal falls off the solenoid (that terminal is just plain stupid, and should be a threaded post not a slide on that can loosen and corrode.  But remember that starter solenoid was installed for a farmer who's on terra firma and accustomed to repairing his equipment -- not to be in an engine that's in one of the worst possible environments (high heat, corrosion, vibration, plus out of sight/mind, impossible to see/access to service, etc.)

3. The starter solenoid should be one with a threaded post "S" terminal, not a quick connect (I have replacements.)

4. The original harnesses had the battery charging current/circuit traveling through the engine gummy bear plug, all the way to the cockpit, through the panel gummy bear plug, to the panel (ammeter,) and back through the panel gummy bear plug, to the engine space, through the engine gummy bear plug again, to the solenoid "B" post.  That's a recipe for at best incomplete charging of the battery due to the voltage loss each step of the way -- and at worst, plug overheating, total failure (corrosion, loose barrel connectors - FOUR of them in the plugs.)

5. Older harnesses had a lighter gauge "S" wire (mine is 16 AWG.)  That's stupid for a critical circuit that needs full voltage/current to energize the critical starter solenoid.  I haven't measured it, but I suspect the solenoid's pull-in amps may be too high for 16 AWG, and for consistent starts it's certainly critical to maintain MINIMAL voltage loss on that circuit.

6. Universal put the harness ground  wire on an exhaust manifold stud.  Stupid - where is constant expansion/contraction and corrosion more prevalent than at that spot?

7. The connections to the engine components were non-marine-grade, non-heat shrink adhesive terminals.  A recipe for corrosion and failure.

8. The pigtail wire itself on the engine side was non-tinned copper.  That would have been acceptable if universal used adhesive-heat-shrink terminals that seal the wire ends, but it did not.  Again, a recipe for corrosion and failure.

9. The terminals CTY/Seaward used at the panel (switches, alarms, gauges, etc) were non-marine-grade, non-heat shrink adhesive terminals.  A recipe for corrosion and failure.

10. The power lead to the panel was 10 AWG - good for 50 amps or so.  But the voltage loss is considerable if you're running the blower, glow plugs, have nav lights on, and trying to crank the starter.  Say it's 25 amps total - that can put you back at the starter solenoid with a little over 11 volts on a good day.  The situation is even worse if you have a 16 awg "S" wire between the key switch and the solenoid.

11. Not part of the harness per se, but the battery ground cable is connected to the bell housing and should be on the engine block (an unused engine mount hole.)

Ken

next - what to mod on the harness and why the "kits" don't solve the problems.

#5

from waterdog

Epic Ken.   Thank you.   Now I feel guilty for asking the question.   But the answer will be here for all...

[Stu Jackson]

As promised, here is the combined material from Ken's writeup.

I've put a link in Critical Upgrades, too.

[mainesail]

11. Not part of the harness per se, but the battery ground cable is connected to the bell housing and should be on the engine block (an unused engine mount hole.)

Engine block would be a bare minimum. I prefer to wire the engine ground direct to the ear of the starter motor rather than pass it through a rusty engine block. The bell housing is just a poor location on a boat..... This wire from the starter ear can then run down to an engine room common neg busbar...

I still often leave the fuse in the solenoid wire (a replacement) unless I have a new starter or solenoid with a stud rather than a Fast-On terminal...

This issue is s not just limited to Catalina, though the Seward equipped boats are a bit worse than some other brands. Don't worry the older Yanmar's are not much better....

We all should agree that the gummy bear plugs are a problem (the hard white plug on the engine side is OEM Universal and is marginally better than the mating gummy bear plug.)  
Universal supplied M-25 and XP/XPA engines with that white, 8-position, "trailer" plug on its engine component wiring that it added to the Kubota tractor engines.  But if they're so bad why are they there? (on new engines Westerbeke/Universal still installs similar plugs.)

Newer engines pass minimal current through these plugs, no alt current for example, and they also use a glow solenoid so no high glow plug current, just an amp or less for 10 seconds or so..

I still believe Westerbeke could step up and use a quality water tight plug from any one of half a dozen vendors of such plugs, but they continue to use bottom of the barrel, el-cheapo trailer type plugs. That said on newer engines with minimal to no current running through these plugs the problems are much rarer... Volvo, Beta, Vetus and Yanmar all use more robust positive locking plugs on their engines but most of them still use Fast-On's for the starter solenoid......

[KWKloeber]

Engine block would be a bare minimum. I prefer to wire the engine ground direct to the ear of the starter motor rather than pass it through a rusty engine block. The bell housing is just a poor location on a boat..... This wire from the starter ear can then run down to an engine room common neg busbar...

I still often leave the fuse in the solenoid wire (a replacement) unless I have a new starter or solenoid with a stud rather than a Fast-On terminal...

Newer engines pass minimal current through these plugs, no alt current for example, and they also use a glow solenoid so no high glow plug current, just an amp or less for 10 seconds or so..

I still believe Westerbeke could step up and use a quality water tight plug from any one of half a dozen vendors of such plugs, but they continue to use bottom of the barrel, el-cheapo trailer type plugs. That said on newer engines with minimal to no current running through these plugs the problems are much rarer... Volvo, Beta, Vetus and Yanmar all use more robust positive locking plugs on their engines but most of them still use Fast-On's for the starter solenoid......

RC,  

Spot on and GREAT point re: to the starter ear.  I would also think so long as a "good" location such as an unused and cleaned up open motor mount location shouldn't be a problem?

Is it your opinion, then, that the gummy bear plugs could still be serviceable (presuming they are in good shape) , if:
1. The charging circuit/ammeter is eliminated.
2. A glow plug slave relay is added.
3. A starter solenoid slave relay is added.
That would remove all high current passing thru the old trailer plugs.

PS, I much prefer using a standard type, continuous-duty, 40-a, headlight relay, over a Ford type solenoid.  Too much real estate, cost, power draw for what's needed.  And the relay is cheap to carry a replacement and easy plug and play if one goes bad.


My Part 2, will include adding over current protection within 7" of the solenoid "B" post (power lead to the panel,) which would negate the need for the redundant fuse on the "S" wire, no?

[attachimg=#]

Re: a suitable plug -- I purchased and was ready to install a heavy-duty Cole 12500/12501 12-pole plug/socket, but then decided I no longer needed to pull my engine for its annual spring cleaning.  Plus it takes up a whole lot of real estate.  So I instead butt-crimped them. That's one hell of a plug for that purpose though, and I may use it behind the panel.

I'd love for us to come up with one comprehensive "Honey Do" Wiki document that would address all the CTY electrical ills/fixes, even if it allows options (butt crimp or terminal strip -- depending on, say, owner skill level or $$$, etc.)  I want to also include other options like, for instance, using the now-spare 10-awg ammeter/charge wire for an upgraded "S" wire, or use a spare wire for a oil pressure sender/gauge.) (ooops I'm getting ahead of myself on my Part 2/3 here.)

Everything is now such a messy conglomerate of suggestions all over the place at this point, I'd like to get them all in one primer so an owner needs to read only once in one location.

Ken