Alternator problem

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May 2, 2008
254
S2 9.2C 1980 St. Leonard (Chesapeake Bay), MD
REVISED Alternator problem

I have searched for an answer and can't find one so I am asking here...Fired up the iron jenny yesterday and noticed that the alternator (I assume it is the original Hitachi 35 amp on my Yanmar 2QM15) was intermittently putting out in excess of 16 V at about 28 Amps. It would do that for a minute or 2 then drop back to much lower (range of 2 to 3) amps and normal (13.x) volts. The increase occurred after it had been running for several minutes.

Any suggestions to correct this problem? If no correction, then does anybody know of an economical drop in replacement alternator? I have new batteries and really don't want to fry them!
 
Last edited:

larryw

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Jun 9, 2004
395
Beneteau OC400 Long Beach, CA
Sounds like a regulation problem. You have the standard builders set-up and you need to optimize it. You're going to have educate yourself 'cause there are too many variables, like how do you use your boat. Get a book or two, and go by West Marine and get one of their big cataloges, they are full of good explanations and advice.
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
I had the same alternator on my 2QM20. It is easily removed and delivered to any auto electric shop. Relatively inexpensive to test and repair. I ultimately upgraded to a 50 amp Hitachi that I found on E-Bay. Both since sold.
 
Feb 26, 2004
23,308
Catalina 34 224 Maple Bay, BC, Canada
Sounds like a regulator issue

First check to make sure the connections at both ends are fine. Where were you reading the voltages?

If the wiring's OK, if it was my boat I'd take it out and do what Larry recommended. Unless you personally can do the repair Maine Sail posted yesterday ro the day before in repairing alternators. See: http://forums.catalina.sailboatowners.com/showthread.php?t=106014
 
May 2, 2008
254
S2 9.2C 1980 St. Leonard (Chesapeake Bay), MD
Re: Sounds like a regulator issue

I was reading the info that my Xantrex Linklite gave me (it is great). I would like to upgrade to more amps if there is an affordable drop in replacement.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Before you pull the alternator

Get a volt meter and measure the voltage on the battery terminals while monitoring the voltage reported from the linklite. Start with a charged battery, start the engine and continue to monitor till the volt meter is indicating that the alternator has settled into trickle charge mode.
I think you will be amazed at how the two disagree.
That is not a bad thing of everything averages out in the long run BTW.
This is just how a stock regulator and the linklite can interact.
Things to check:
Does the linklite monitor the system voltage at the alternator or battery terminals? Battery terminals are preferred
Are all connections clean and tight? Corrosion will play havoc with the linklite sensing circuit.
Do you have a reefer turning on and off muddying the waters and changing the circuit voltage?
 
May 2, 2008
254
S2 9.2C 1980 St. Leonard (Chesapeake Bay), MD
Re: Before you pull the alternator

The Linklite was installed just a few weeks ago (good, clean connections) and was installed per instructions at the batteries. I would not have thought there was a problem except I noticed the voltage was above 16 (it should be just over 14) when the amperage increased as evidenced by the Linklite, the boat's ammeter and the distinct sound of the alternator putting a significant load on the engine at idle. I will check the alternator connections to make sure they are clean and tight but I am suspecting that the internal regulator (in the alternator) might be going bad. It was not consistently high but stayed on long enough that I would be concerned that the batteries might be damaged and if the alternator is in the process of going bad, I don't want to wait until it dies completely.
 
May 2, 2008
254
S2 9.2C 1980 St. Leonard (Chesapeake Bay), MD
Re: Before you pull the alternator

I forgot to add that there was NO load - everything was turned off at the panel (and I could only wish for a refer.)
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Alternator Problems

I had been wanting to upgrade the stock 35 amp Hitachi for some time now, and just recently did as part of spring get ready to sail. I took my old 35 amp to a local starter, and alternator shop. I walked out with a 70amp Hitachi, for 70 bucks, and kept my old alternator for a spare. Like some others, I am happy and comfortable with the stock built in regulator, so left all that alone. Here's what you need to look for. The 70 amp is a larger bodied alternator, but the mounting base is identical. The only thing you need to change is the ear that the tensioner arm attaches to. Looking at the alternators from the pulley side, the stock 35 has a mounting ear for the adjuster arm directly across from the mounting feet. The one you want needs this mounting ear offset to the left. I don't think it is 45 degrees, but probably 30 degrees or more. There are only one or two alternator cases, so will be easy to tell.This lets the adjustment arm clear the larger body. Thats all you need. I also increased the wire size from alt. to battery, as I didn't think the 12ga was quite heavy enough,and put a 60amp fuse in it. Used 8 ga wire, which should be plenty heavy, and it doesn't take much wire. If you connect at the starter terminal, where most do, about three feet of wire is plenty. Good luck and good sailing.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
I would also suggest that you take it to a auto electric shop and have it tested before you jump to any conclusions. If it is bad, it may be an inexpensive repair. If it is not a simple repair then you can consider a replacement.

Check out the Yanmar Hitachi rebuilts/remans. I was told by a good source that these units are actually new units (around $300). They can be had for about the same price as a retrofit unit that will probably require modifications.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Face the facts

First off, if this is the origional, which he suspects it is, it is over 20 years old. Closer to 30 probably. Think the last year for a 2QM was approx. 1980. The regulator in it is probably bad. Possibly not, but likely it's bad. He can take it to someplace like auto zone, and have it checked for free, but when I tried that, they couldn't tell which adapter to use, without a make and model of the car it came off of. Yeah right. He stated he would like to switch to a bigger alternator. Why in the hell spend time and money, on something 30 years old, and probably bad to boot, when you want to replace it anyway. A good alternator shop can take one look and know exactly what it is. The Yanmar alternator is a Hitachi. Exact same thing, except for a 200 dollar price difference. There is no marine alternator for a diesel engine. The only difference in a " Marine" alternator, and a regular alternator, it the little screens inside it to keep small hot pieces from slinging out. Save a lot of time and money, pull that puppy off, and take it to a good alternator shop. JOB DONE
 
Sep 25, 2008
1,096
CS 30 Toronto
Alternator replacement

I changed to a rebuilt Remy-Delco off a GM truck. It pump out 70A max. The auto-electric shop tap out the connection for the tachometer. I extended the regulator sensing wire to the top of the battery. Also made a dog-leged arm. I happen to have a #1 cable for the battery, wrong color but who cares. Total cost $70.00. I still have the original as spare. See photo
 

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May 2, 2008
254
S2 9.2C 1980 St. Leonard (Chesapeake Bay), MD
REVISED - Alternator Problem

It seems that I do NOT have the original alternator. I took it off today and can't find any numbers or other manufacturer markings on it. It is NOT internally regulated. I have a Transpo M5-130A external regulator (12V 070). Now my question would be can I replace that regulator with any "B" type regulator or does it have to be matched to the alternator. I'm assuming that it is the regulator that is bad - it was pumping out a little over 17 volts this morning as measured at the batteries by the Linklite monitor as well as my handheld multimeter.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Check your connections first

Corroded connections in high amp circuits can cause problems. you need to figure out where the regulator is sensing voltage. If the sense cable is corroded the regulator will "see" a lower voltage and increase it till it sees the right one. It may also be possible to adjust the regulator voltage down.
 
Oct 16, 2008
19
Irwin 38 MKII Center Cockpit West Island
I changed to a rebuilt Remy-Delco off a GM truck. It pump out 70A max. The auto-electric shop tap out the connection for the tachometer. I extended the regulator sensing wire to the top of the battery. Also made a dog-leged arm. I happen to have a #1 cable for the battery, wrong color but who cares. Total cost $70.00. I still have the original as spare. See photo
Just a peice of advice here. I also did this mod a few years ago on my old boat. Since then i have heard that Automotive electrcal components like alternators and starters are not rated for marine use due to them not being insulated against arking and sparking internally. Now for most of us sailors with desiel engines but if you had a gas engine and you had a spark from your alternator...well i dont have to continue...the problem is that your insurance company may not pay due to improper electrical equipment installed on board... The ABYC can provide you more information on this...
 
Feb 26, 2004
23,308
Catalina 34 224 Maple Bay, BC, Canada
There are other reasons for not taxing an automotive

Since then i have heard that Automotive electrcal components like alternators and starters are not rated for marine use due to them not being insulated against arking and sparking internally.
...alternator with an external regulator. They're not made for the heat! Think about it: the car battery is almost always full, just like your reserve bank on your boat, so when the alternator is running it is not being asked by the regulator to put out a lot of current.

But add in a depleted house bank and the alternator has to run like blazes to charge the house bank. That's simply NOT what an automotive alternator is designed to do, sparky or not!:):):)

See these:

http://c34.org/bbs/index.php/topic,4454.0.html

http://c34.org/bbs/index.php/topic,4787.0.html

http://c34.org/bbs/index.php/topic,4669.0.html
 
Feb 6, 1998
11,756
Canadian Sailcraft 36T Casco Bay, ME
If you're crafty

If you're crafty and do a little research you can find real marine alternators for MUCH less money than Balmar.

These two alternator photos were taken on the counter of my Westerbeke/Universal distributor.

This first one, the #300746 is the direct 72 amp upgrade from Universal and Westerbeke and is a Leece-Neville 8MR2026PA. It sells for $573.46 if you buy it from a Westerbeke/Universal dealer or can order this same exact Leece-Neville alternator from ASE Supply for about $240.00. they are very easy to convert to external regulation using the Leece-Neville conversion kit.


This next one, part #30735 is a 90 amp version of the alternator above. It is a Leece-Neville 8MR2070TA it uses the same exact mounting feet, bolt centers and off sets as the 72 amp version and is also very easy to convert to external regulation.

Here's a 90A version


Something many don't know... Leece-Neville is a manufacturer for some Balmar units, built to Balmars specs of course. Their 8MR series alternators used to be sold by Balmar and are pretty comparable in build quality to the one Balmar used to sell.. The black one, or the 90 amp version above, is even epoxy coated using the same paint Balmar does only in black.

If you own a Universal engine, as many here do, Balmar does not really sell one that won't need some slight modifications for belt alignment and fit but the Leece-Neville is as near a drop-in as it gets. Is teh Balmar 6-Series a better unit, absolutely, but it costs $600.00 vs. about $300.00.

Total Cost

Pulley:
Please don't ignore the fact that the Leece-Neville 8MR will need a pulley, and most are a 5/8" shaft which is non-standard. The factory available pulley is cheap stamped steel and sells for about $45.00 - $60.00. Billet machined pulleys don't really exist in this size so I have them machined at a cost of about $75.00 each. Cheap stamped steel pulley's are fine for cars with little demand, but stamped steel expands under high load due to heat and leads to increased belt wear & slippage.

Mounting Kit:
The foot on the 90A and 105A are 1" wide with a 1/2" diameter hole requiring a 1" to 2" special shim kit. This kit runs about $30.00 - $45.00 depending upon the source. Be aware that some sell the wrong kit or a kit that lacks the special sleeve so the unit can be used with a 3/8" pivot bolt or a 10mm pivot bolt.

External Regulation Kit:
These kits are all over the map price wise and can be hard to find actually in-stock. While many sites will show the kit they don't actually have it and most can't even get it when you ask. Before you order one pick up the phone and ensure it is in-stock. These kits run from $19.00 to over $35.00..

The total cost of this upgrade is not just in the alternator. Expect to be in the $300.00 to $340.00 range to do this the right way using the right components..

I have never had a failure running a Leece-Neville 8MR series externally regulated unless the regulator was improperly set up. They really need to use Belt Load Manager level 3-4, plus the alternator temp sensor, or they have not been properly set up.
 
May 2, 2008
254
S2 9.2C 1980 St. Leonard (Chesapeake Bay), MD
Re: If you're crafty

As I said in a previous post, I don't know what alternator I have - only know that it is external fan and externally regulated. Having said that, the 'footprint' (mounting bracket and shape of case with exception of the rear portion) looks exactly like the Leece-Neville (or Leece-Neville / Motorola). Is anybody familiar with this brand of alternator and what sizes (amps) they made in the last several years?
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Why alternators go bad

With the exception of warn slip rings and brushes, alternators don't wear out. Even after 20+ years.
If you are seeing high output voltages check the grounds on the alternator. If the unit has a "body ground" then check for corrosion on the brackets. This can cause lots of issues, espesically after a few years.

Good luck.
 
Feb 6, 1998
11,756
Canadian Sailcraft 36T Casco Bay, ME
Leece-neville makes

As I said in a previous post, I don't know what alternator I have - only know that it is external fan and externally regulated. Having said that, the 'footprint' (mounting bracket and shape of case with exception of the rear portion) looks exactly like the Leece-Neville (or Leece-Neville / Motorola). Is anybody familiar with this brand of alternator and what sizes (amps) they made in the last several years?
Prestolite / Leece-Neville is one of the larger manufacturers of alternators. The make literally hundreds of models in about 30-40 different frame or series types.

In the 5" case style I showed above they make amp outputs anywhere from 37 to 105 amps.

Here's a link to just their 8MR marine series alts.

Leece-Neville 8MR Series Alternators (LINK)
 
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