Universal engine harness upgrade - here's why

[Sefuller]

There are lots of threads about the importance of replacing or upgrading the engine panel wiring on many of the older Universal diesels due to the high current passed through long runs of undersized wire and trailer plug connectors. During the replacement I am working on currently I discovered an extra couple YARDS of wiring harness bundled up behind the panel

 

[Tom J]

Jeez. When every foot of cable adds to voltage drop! They probably didn't want to cut the cable to length and reinstall the connector.

 

[LeslieTroyer]

I rebuilt my harness last winter. Weather oak connectors at engine panel and terminal strips at the engine. No high current thru the harness additional 60/40 relays for both glow plugs and starter relay. Works fantastic.

 

[Stu Jackson]

There are two meanings of Universal:

1. Engines made by Universal (Catalinas, O'Days, many others)

2. Universal meaning used in many many different applications and with engines that are NOT made by Universal (Yanmar, Perkins, etc.).

Please understand that those trailer plug connectors are the major source of the problem. The other half of the issue is ammeters in cockpits, where the AO goes to the cockpit panel through horrendously undersized wire and then back to the battery bank, usually through the C post on the switch. In most cases (except for the ammeter wire concept itself) the wires are OK, it's the connectors and the cockpit ammeters that are the main issues.

Universally.

 

[FastOlson]

Last year I measured the temp. at each "trailer plug" on my 1988 Universal M25XP. I used a new remote readout with a laser pointer. Pretty neat device, BTW.
Our original installation had less surplus cabling coiled up than yours, but each plug was not only warm to the touch but actually measured 10 deg.warmer than ambient. (not good at all)

I was going to replace all of the old wiring (and get rid of the factory amp meter, as well...) but after assessing all that needed doing on the old drive train I replaced everything with a new Betamarine 25, which included a new panel.
Just wish I had done this years ago! It's quiet and now there are no more oil leaks. I have some pix in my blog at ericsonyachts.org if you want a link.

 

[wing15601]

I checked my ammeter today and found it is connected with the trailer wire connectors. I thought the previous owner had corrected the problem because the ammeter doesn’t work anyway. Here is the reason for this question. In southwest Michigan the beginning of summer has been really crappy and as it’s just now warming up I don’t want to lose any more sailing time with a major rewiring project. I’ve thought of following the advice given by many Universal 5411 owners and use a 1/0 cable to connect the alternator output to the positive battery post on the starter solenoid but instead of messing with removing the currently in place wiring just leave it until this winter where I can work on it under the winter cover. My thinking is that the large cable providing the alternator output to the batteries in parallel with the existing 10ga wire will greatly reduce the current flow through that smaller wire therefore greatly reduce any over heating? Is this a bad idea?

 

[LeslieTroyer]

Safety items especially fire hazards should be addressed promptly. Getting rid of the trailer plugs only takes a couple hours, but if you’ve already put a direct link from AO that bypasses the engine panel, your safer, other big draws causing fire hazard are glow plugs if relay mod not done, and to much smaller chance starter relay wires. If you’ve done. The GP mod and the connectors are not burnt and melted your probably safe enough.

 

[wing15601]

Ok, I disconnected the orange wire from the alternator and the ammeter and taped the ends. The red wire is still connected to the ammeter, which never worked anyway, and there is also still a ground on the ammeter. I haven’t removed the gauge because I think that red wire supplies power to the start switch through the ammeter. Now when I turn the ignition switch to start the ammeter needle moves to the discharge side while the starter is engaged. As far as I can tell my gauge panel wiring matches the Universal Diesel engine connections and panel connections diagram except on the ammeter the ignition switch is connected to the red wire stud, not the orange wire stud. Does anyone see a problem with this? Can I just connect the #5 red wire to the lug on the ignition switch where the ammeter was connected and remove the ammeter?

 

[Stu Jackson]

Here's the original Catalina write up about the ammeter. Only you can tell where your wires are on your cockpit. Learn how the power actually runs to decide what is the right thing to do.

• Engine harness upgrade: A comprehensive overview by Gerry Douglas Important WARNING for M25 owners
  
• Engine Harness Upgrade from Maine Sail http://www.pbase.com/mainecruising/universal_wiring_harness_upgrade and http://forums.catalina.sailboatowners.com/showthread.php?t=135558

 

[Richard19068]

Can I just connect the #5 red wire to the lug on the ignition switch where the ammeter was connected and remove the ammeter?

Yes, you can do that. That's the way mine is. But if you are going to remove the ammeter you might as well put in a volt meter to fill the hole though.

You didn't say so in your second post but I assume you did run a heavy wire between the alternator output and the starter positive as you said in your first post. Otherwise when you disconnected the orange wire you left the alternator output with no place to go.

I would suggest you also replace the yellow/red wire (#3 on the diagram) between the start button and the starter with a heavier gauge wire (maybe #10). Just bypass the trailer plug and use a fuse holder and appropriate fuse.

If you haven't yet you really should read Main Sail's how to on this issue.
https://marinehowto.com/universal-diesel-engine-wiring-harness-upgrade/

 

[Stu Jackson]

Nice to see consistency here! Multiple links to the same Maine Sail article. Great!

 

[Richard19068]

Nice to see consistency here! Multiple links to the same Maine Sail article. Great!

Best advise west of Nova Scotia. And it's free!

 

[wing15601]

Thank you all for your replies and for sharing your knowledge. Yes, Richard19068, I did install the 1/0 cable from the alternator output to the starter. I have also printed two copies of Main Sail’s how to article and keep one one the boat, one at home, along with printouts of the engine and instruments wiring. I’ve studied them closely. I’m enclosing a photo of the rear of the ammeter gauge before removing the orange wire. There is a red wire, connected to the same post as the orange wire, going to the “BAT” terminal or the start switch. I think that wise should be connected to the other terminal of the ammeter, the one with the red wire. I think that’s why the ammeter didn’t work.

 

[LeslieTroyer]

It was wired right, on if it was on the red side you wouldn’t see the drain from the panel. Now the orange wire is gone connect the long red wire on the amp gauge to the switch where the short red is and toss the short red wire.

 

[wing15601]

Thank you.