Alternator/Voltage gauge problem, 5411 diesel

[Marcobowow]

Hi, this is my first post,

I'm trying to decide if I need to purchase a new alternator for my Universal 5411 diesel engine, serial # 302296.

The voltmeter gauge on my instrument panel wasn't functioning when I purchased the boat. (1982 Catalina 27).

I overheated the engine, destroying the impeller and during that, the water temperature gauge quick working.

I replaced both the water temp gauge, voltage gauge, and impeller.

The engine and the water temp. gauge are fine, but the voltmeter pegs all the way to the right at 16 on my gauge.

I put a multimeter on the battery with the engine off and it read 12.79 volts.

When I started the engine, I checked it immediately and it was 12.44 and after about 6-8 minutes, it was still 12.44v. However, I've never had any problem keeping the battery charged.

I did notice that the first time I started the engine, after replacing the new gauges and impeller, the voltmeter gauge on the instrument panel appeared to work correctly for about 8 seconds, then pegged to the right and stayed there, even when I started the motor again.

Do you have an idea what might be going on?

Thanks for any help.

[Rockter]

Marco :

12.44 V is too low for charging.

It needs to be higher than that.

[Marcobowow]

Rockter,

Thanks for the reply. That was the first time I've ever checked the voltage while the engine was running, with a multimeter. I checked it several times and at different RPMs, but it was always 12.44v.

I've been reading and I'm going to check the connections, see if anything is loose. Check for voltage drops on the negative and positive sides, saw that on Youtube.

If everything checks out okay, I guess I need a new alternator, but I've never had any problem with the batteries not being charged properly and the PO said the same.

Thanks again, thought I was going to have a shut-out.

[MarkSF]

I wouldn't write the alternator off yet. To produce the correct output it needs to have the correct circuit in place.

Some alternators have a separate sense wire. If that is not connected to the battery, the output will go to full regulated output.

Take a look here, at the wiring diagram.

http://www.ewmanchester.com/CalDocs/...s%20Manual.pdf

This shows an ammeter. Are you sure you didn't just replace an ammeter with a voltmeter? If you did, this is the source of your problem. The alternator is putting out full charging voltage, but the voltmeter has far too high a resistance for it to reach the battery.

If a voltmeter is correct, it sounds like a wiring fault - which can include a high resistance connection somewhere. You should carefully examine and troubleshoot all wiring.

An interesting test would be the DVM across the back of the voltmeter to see if that 16V is real.

[Marcobowow]

Wow, you're right. I found the old gauge, and it's an ampere gauge, just like the manual shows. I totally assumed it was a voltage gauge. Gosh, I wonder if I should be working on my boat. I have a pic of it too.

I'd guess that's why the high reading.

Unfortunately, the multimeter says my alternator is only producing 12.44v, that's another problem.

Do you suppose having the wrong gauge installed could affect the alternator output?

[Marcobowow]

CatalinaDirect doesn't even sell an amp gauge. All they have is voltage gauges and all their new panels have voltage gauges, no amp gauges.

Seems like having a voltage gauge would be more important than having an amp gauge.

Is there a way to convert to a voltage gauge? Wonder why they originally put an amp gauge in there?

[MarkSF]

Originally Posted by Marcobowow

Wow, you're right. I found the old gauge, and it's an ampere gauge, just like the manual shows. I totally assumed it was a voltage gauge. Gosh, I wonder if I should be working on my boat. I have a pic of it too.

I'd guess that's why the high reading.

Unfortunately, the multimeter says my alternator is only producing 12.44v, that's another problem.

Do you suppose having the wrong gauge installed could affect the alternator output?

An ammeter normally sits in line between the alternator and battery, thus measuring the current that flows. A voltmeter would not be inline, as it has very high resistance.

Yes, the wrong gauge can easily be messing up the alternator output. Let me go further, it IS messing up the output.

You can have a voltmeter, an ammeter, or both - but the wiring has to be appropriate. You can't interchange them in the same place in the circuit.

As a simple test, connect the two wires at the back of the voltmeter together. I think you'll find the alternator starts charging correctly. Or just put the old ammeter back in. Are you sure it was bad? If your batteries are charged by a shore charger it won't read much current when the engine's running. But you should see a nice discharge when the glow plugs are being heated.

I'd be fairly confident that a gauge like this will work :

http://www.defender.com/product.jsp?...261&id=1674468

You don't have to go to Catalina direct. You're just spoilt anyway Try owning a boat by a builder that went bust 20 years ago. No Bristol Direct for me, just have to find a part that fits.

[Maine Sail]

Originally Posted by Marcobowow

Hi, this is my first post,

I'm trying to decide if I need to purchase a new alternator for my Universal 5411 diesel engine, serial # 302296.

The voltmeter gauge on my instrument panel wasn't functioning when I purchased the boat. (1982 Catalina 27).

I overheated the engine, destroying the impeller and during that, the water temperature gauge quick working.

I replaced both the water temp gauge, voltage gauge, and impeller.

The engine and the water temp. gauge are fine, but the voltmeter pegs all the way to the right at 16 on my gauge.

I put a multimeter on the battery with the engine off and it read 12.79 volts.

When I started the engine, I checked it immediately and it was 12.44 and after about 6-8 minutes, it was still 12.44v. However, I've never had any problem keeping the battery charged.

I did notice that the first time I started the engine, after replacing the new gauges and impeller, the voltmeter gauge on the instrument panel appeared to work correctly for about 8 seconds, then pegged to the right and stayed there, even when I started the motor again.

Do you have an idea what might be going on?

Thanks for any help.

Please take the time to read this thread.


Universal Engines Wiring Harness Upgrade (LINK)

[Marcobowow]

MarkSF,

Thanks for that. You've been very helpful to me. I'll go to the boat, which I've owned since July of this year, and either get the new gauge, or hook up the old one and see if my alternator voltage improves.

I bought this boat in July of this year. I've never owned a large sailboat, just lasers and hobie cats, so this has been quite an education, and expense. Actually, it's been fun, especially learning about a diesel engine.

Marine Sail I haven't read that article, but I will, thank you too.

I'll get the proper gauge back in the boat, which could take a couple of weeks due to Christmas, and I'll post how it went.

Thanks,
Mark

[Capt Len]

Putting a full current ammeter on the dash by the compass can have an interesting effect on your ability to steer a course. Better ammeters are actually measuring voltage drop across a low ohm resister in the output wire from the alternator(Ohm's Law stuff) If you do have to have current carrying wires near the compass make them twisted sisters to negate the magnetic fields.