Need alternator help

[rwappleton]

We have shucked an alternator on our 43 DC. She has J&T 6-71TI's 390 HP. 12 volt system

Does any one know the part number and amperage output? The unit has NO visible outside markings. My son who works for NAPA and is the rep for alternators can't even identify it.

How about sources for rebuilt and or replacement? I am calling Sam's later today.

Any information would be helpful. According to my son this one is most likely not rebuild-able. The case is broken (go figure) and he said it looks like it was "under the boat" very corroded.

As always thanks for the help!!!!!!!!!!!!!!!!

[Boatsb]

Is it belt driven or gear driven from the engine?

Bring it to a good marine alternator shop and see if they can get one. If not maybe they can find a rebuildable core.

[Will]

We have the same engines and I believe the alternators are 100 amp.

But, your best bet is to get your engine serial number and contact J&T. They should have the info you need.

Will

[rwappleton]

Scott,

The core is trashed. I just got a look at it via skype (ain't technology great!) Belt driven and it's trashed I do not know how it was doing anything. As I said #1 son is Alternator rep for NAPA and he can not ID it other than it is a Delco unit with markings and tags long gone.

Will,

Do you have a number for J&T?

Thanks,

Russ

[Boatsb]

I brought mine into a shop that does marine work and he had rebuilts on the shelf. They are delcos too. Napa may not be able to match old discontinued units.

[Andy B]

They are 80amp I believe I just replaced one of mine and I have the same engines as you do, they are delco as said earlier I opted for an 140 amp replacement ,just need to run two belts , any good alt shop should be able to get you a replacement .

[Kim Beatley]

Another Alternator Question

I need to replace both of mine. However one turns clockwise, and the other counter clockwise. Do you have to specify rotational direction when you order one?

[rwappleton]

Kim,

I am not sure on gear driven due to the angle of the gears. Belt driven does not matter. It will make power either way. I am told there is a 140 amp replacement but unless you are powering the entire boat on inverters and only running the engines I do not see the need.

[Glory]

You might want figure out what you need in terms of amps instead of what you had. Many boats are running options that didnt exist in 20 years ago, so do the math.

Even brushless is something you might want to think about, like a Delco 35SI. Extra amps normally don't change the price much.

As for rotation the alternator can go either way.

JM