Do I need to replace my alternator, and if so, how do I choose one that will work?

Posted by ___xXx__xXx__xXx__@reddit | sailing | View on Reddit | 29 comments

My batteries are not charging from my alternator. They do charge from a solar panel, and mains plug in charger, so I think they're fine. I've run the engine at idle, and in gear, and given it a good wait before measuring with a multi-meter. I get the same voltage on the battery, and on the alternator pins, whether the engine is on or off.

Is there anything else I should try before paying the money for a new one, or is that about the gamut of diagnostic options?

Assuming we're assuming it's done, how do I make sure I get the right one? Mine has absolutely nothing written on it (and the engine has no code on it, just says Beta Marine/Kubota). I'm not really sure what parameters I need to match up.

There's so many on ebay that appear to be the *identical* design, but at various amperage. Could the measurements be different even though they look exactly the same?

To be clear this is the first engine I've ever dealt with. Thanks.

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Dstyle90@reddit

Do you spray your engine with wd40 every once in a while? It should not corrode that much, even within a long period

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_xXxxXxxXx@reddit (OP)

Only just got the boat. It was that way when I got it.

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Next-Juggernaut7404@reddit

You can check if the alternator works if you measure directly on the unit with an multimeter. Being an boatbuilder myself I would just by looking at the picture, say it’s dead. I would replace it instead of trying to fix it.

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Sir-Realz@reddit

looks like a Small Block Chevy Alternator, the cheapest with the most options. I'd recycle that POS or use it a a boat anchor. I'd get a high amp model or I like my chrome one from DB Electric in my EL Camino 6 years lol

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pedal-force@reddit

I didn't realize what sub I was on and was going to ask if you regularly drive your car into salt water.

Carry on.

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ramkitty@reddit

Rebuild or replace. It is very corroded and the bearings probably need replacing. It could be as simple as the voltage regulator. The alternator appears to look like a small block Chevy alternator. Wire brush some of the aluminum housing near the joint, should reveal some cast markings

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overthehillhat@reddit

Good call--

My Alternator guy told me some installs use a rogue alternative

instead of original specs

we always need to do our homework

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Paleolithicster@reddit

Call Beta Marine

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_xXxxXxxXx@reddit (OP)

To ask what?

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HotMountain9383@reddit

They will tell you where to pull the engine code or identify it from a photo and then spec you a new alternator.

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Paleolithicster@reddit

Yes (sorry for my short response earlier OP) exactly this. They’ll know how to identify it and at least give you a model you can then google replacements for if you don’t want to or can’t get the OEM version

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JorgMap@reddit

Looks like a Lucas A127 alternator.

It may be worth trying to figure out if you can swap it to a GM one wire alternator though. You would just have to figure out the mounting.

https://youtu.be/wq2LrI6uk7U?si=VwHeDtwKUxAq4-nj

https://www.mgexp.com/article/delco-alternator-conversion.55

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_xXxxXxxXx@reddit (OP)

I'm sure that's better, but at my level of expertise I think I'll keep it simple and just replicate what's already there.

So can I just get any Lucas A127 alternator that is correct hand side and powerful enough, and I'm good to go? Is that the keyword here "Lucas A127"?

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T4whereareyou@reddit

Your alternator probably needs replacement. You need to find out what the make and model of the engine is, and from that look up what was specified for it.

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_xXxxXxxXx@reddit (OP)

I don't know how to find out what model the engine is. The make is Beta Marine. The engine has no other writing on it anywhere but where it says Kubota and Beta Marine. I've looked all over the internet to try and identify it.

Is there not such a thing as a fairly generic alternator that would fit several types of engine? Can I not just get one with the same bracket, and pulley type?

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kyler000@reddit

Try using Google lens to identify it. Using the picture in your post I found this in about 5 seconds. Looks pretty close to what you have.

https://www.iat-usa.com/product/a755-lucas-marelli-a127-type-alternator-for-ford-backhoes/

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_xXxxXxxXx@reddit (OP)

Yeah, I see, thanks. There's a ton on ebay that look exactly like this (like exactly), and they often say "Lucas type" and A127. I don't know enough about engines to know if that's enough to go on and just buy one.

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kyler000@reddit

Try using google lense on a picture of your engine. Hopefully from there you can get a model number and do a deeper dive on the what alternator it uses.

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_xXxxXxxXx@reddit (OP)

Okay, thanks.

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jonathanrdt@reddit

No. Alternators are not standard. They are almost infinitely variable even among one that appear to be the same. Size, power, mounting brackets all vary wildly.

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Cambren1@reddit

Take it to an auto electric shop and have it rebuilt. The cheap ones from EBay often don’t work or even fit. The one from Kubota may be very expensive.

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_xXxxXxxXx@reddit (OP)

Take it to an auto electric shop and have it rebuilt.

This thing is really worth that kind of money?

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MandatoryAdventure@reddit

absolutely not! Just but a solid one with a warranty froma known manufacturer. they aren't an expensive part

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_xXxxXxxXx@reddit (OP)

That's what I suspected. There's a ton of these on UK ebay:

https://www.ebay.co.uk/itm/281429602654

They appear to be absolutely identical to mine, apart from the pins are little different on the back. Can I just get one of these, do you reckon?

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bernoulli33@reddit

This, or buy an entire replacement from the shop. They can make sure you’ve got the right connections and format.

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dawa43@reddit

This is what happens when cheap automotive parts get used in a marine environment.

Time for a new one.

Either get another cheap one and replace it again next year (maybe 2 years) or pay for the marine version... Your wallet will help you decide.

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