I need to replace my Mitsubishi 50 amp alternator. Does anyone know the model number, or where I can purchase a replacement? My engine is a Westerbeke 13 h.
Thanks
Howard Whittaker
N26 #18
Stray Cat
Prince Edward County, Ontario
One suggestion would be to go to any auto parts supplier with a photo of the front and back since you already know it’s output. I assume the label is missing from the unit. If purchasing from a none-marine oriented supplier, make sure it’s rated for marine use.
Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA
Kingston Auto Electric
830 John Counter Blvd, Kingston, ON K7K 2R1
He’ll either rebuild it or get you a new one..
Old friend of mine…
Before you take it out, take a photo of the back so you know for sure there the wires go. 3 lugs, 3 wires, where do they go?
The alternator on my W13 was definitely the Mitsubishi 50 amp that is shown on page 70-74 in the Westerbeke technical manual.It was easy to take apart and clean, the brushes were still good so i put it back together and it is working fine. I’m sure a shop could rebuild one of these easily.
At the time I looked for an alternator that would drop in. An old Toyota alternator looked like it would fit but my old one works so I didnt try it.
There is a new replacement for the obsolete one on the Westerbeke site.I See below. $794US from Westerbkeke.
If you find one that fits please let us know the model.
Thanks
Tom
26C #28 W13
The alternator has to be one for a diesel I believe or else it won’t have a tach connection. That narrows the search.
For the original style, this one says it is a replacement for the Westerbeke. It differs only slightly in a couple details on the back. Says it is new. Unfortunately doesn’t ship to Canada.
https://www.obbstartersandalternators.com/20061n-a002t25271-a002t25271zc-mm409650-030594-049246-p-4625.html
This one looks like it would work and resembles the new Westerbeke, is for a diesel and says it fits various Westerbeke engines. However it is 200 amp.
https://www.obbstartersandalternators.com/12715n-0124625044-al9963sb-87715398-5264312-mg225-p-500.html
There are also some on Alibaba, shipping from China but these look like copies. That doesn’t mean the new ones above are not also a Chinese copy, they probably are.
Tom
26C #28 W13
Penetang
For a Westerbeke 13 the old part number was 30594 (discontinued) and has been replaced with 49125. This new alternator requires a modification to the spacer (I believe you can buy a new appropriately sized spacer if you don’t care to modify your existing one.
QUESTION:
Does anyone know which of these is used (see picture). The “R” is for Regulator and the “L” is for Light. I’m just not sure where this wire leads to (tucked away in the wiring harness).
I have always found the most economic method of dealing with alternators , starters and halyard winches is to drop them off with your local trusted auto electric shop for rebuilding . Around $100 .
Bob Jenkins
Past owner Good News
Aurora ON
L is a Gray wire. Referred to as “Light”. It goes into the wiring harness and could have gone to the Alarm buzzer. I guess was intended to alarm if the voltage dropped but on both the schematic and drawing, Admiral Panel, it is not connected to anything (our oil and water temp sound when the sensors short to ground but this lead does something else. Manual says the L has an internal Lamp relay and is only used for the panel light on the “Captain panel” .This “Captain” panel has warning lights. L wire was connected to an ALT warning light but has diodes in the circuit to fix the logic .
R is a Pink or Blue. R for Regulator? R is also referred to as EXE for excitation. it is Bat+ from the ignition switch and energizes the field coil. There must be +12v on this terminal when the key is on or the Alternator won’t work. It must be from the ignition or it will drain your battery with the engine off.
P is brown. This brown wire runs through the harness to the Tachometer in the engine panel.
B is the battery +
To work the alternator needs at a minimum: a ground to the case, + voltage on the R, and Battery positive hooked to the B terminal. P and L are not required.
That spacer is just a fat washer or a short tube. It was on the Westerbeke parts list for about 20$.
Tom
26C #28
Penetang
On Tuesday, 27 April 2021 at 08:25:34 UTC-4 Val NS26C #75, Ottawa, ON wrote:
Hi Val
Underneath the red wire on your B terminal there is a noise suppression capacitor. You may want to look at replacing or removing this one as it appears to have arced to the case and probably isn’t working anymore.
https://www.westerbeke.com/Product/CONDENSER/030252
Tom
26C #28
Penetang
On Tuesday, 27 April 2021 at 08:25:34 UTC-4 Val NS26C #75, Ottawa, ON wrote:
Absolutely, Bob.
Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA