3.0l not charging battery

I have a 1991 Stingray with a 3.0L motor. Serial is 0D427773 on the motor. Fully charged group 27 marine battery, went for a 1 hour shake down ride on the 14th of May. Was out all memorial day weekend with zero problems. Then last weekend, towed my friend around on the tube for about 20 minutes. Shut down to yank him in and it wouldn't restart. Battery was acting dead, the motor would crank over about one rotation and that was it ...

Yesterday I pulled the battery and had it load tested without charging. The auto parts store told me the battery was low at 11 volts and needed charged but was OK. The battery, best I can tell, is two years old. (The boat is new to us)

Am I correct in thinking this is the alternator? The guy at the auto parts store told me he would be happy to bench test the alternator for me. Is there anything else I should be looking at? Corroded connections? Bad ground? Should I put a bunch of cinder blocks in it and sink it?

The boat is running awesome otherwise...

Thanks for the help and sorry for being a little long winded!

Re: 3.0l not charging battery

Could be a number of things. I would have a look at all connections. Also when running the engine see what the alt is putting out, with a voltmeter. Look at battery cables and connections. Clean, cover with grease and retighten.

Re: 3.0l not charging battery

Follow this service bulletin before you take anything apart.

Re: 3.0l not charging battery

Ok, Thanks guys. I had read a similar procedure in the service manual. I just didn't know if any one had came across the same problem and knew of something to check. I have a date with the boat tonight if it stops raining here. I will report back on what I find.

Re: 3.0l not charging battery

I just didn't know if any one had came across the same problem and knew of something to check.

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Many (Most) times, there are more than one thing that can cause the same exact problem. Just because one person had a wire loose, doesn't mean yours has the same thing. You could have a bad regulator. It just doesn't matter what someone else had wrong, it's what you have wrong.

Re: 3.0l not charging battery

11 volts is plenty to turn over,Maybe Bad brushes in starter,just one thing to think of.Next time it happens use a small hammer and give the starter a good tap.

Re: 3.0l not charging battery

Well, I tested everything, checked grounds and the last thing I did was fire it and test the alternator. I was getting about 12.3 volts at the battery (on a charged battery) and 10-11 on the posts on the alternator. I am going to have the auto parts store double check it, but I am 99% sure its my problem. Thanks again guys!

Re: 3.0l not charging battery

Sounds to me like alternator. Follow instructions as per Don, and youll be good

Re: 3.0l not charging battery

11 volts is enough for your ying-yang, maybe!

Re: 3.0l not charging battery

I am going to have the auto parts store double check it

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Do yourself a favor and take your alternator to your local Starter/Alternator repair shop. Most towns have one, look in the phone book.
Taking it to an auto parts store may not have anyone their that knows how to test it properly, let alone fix it.

Re: 3.0l not charging battery

Don S said:

Do yourself a favor and take your alternator to your local Starter/Alternator repair shop.

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Thanks Don. I looked one up and it seemed like they had good reviews. I took it over there and it will cost $30 plus parts. The lady working the front desk was pretty knowledgeable and said it could be repaired today, depending if they had parts in stock or not. I did take it to an auto parts store and they came up with about the same voltages I did on their test machine. I will wait and see what I hear from the repair shop.

Re: 3.0l not charging battery

Well, heard some bad news from the alternator shop. The guy told me it wouldn't be worth repairing because he couldn't even get the thing open. Seems a little weird, but he said bolts were breaking on the housing and advised me a new alternator would be the way to go. Somehow, even though it costs a little bit more, I do feel a little bit better about that. Let the shopping begin!

Re: 3.0l not charging battery

Seems a little weird, but he said bolts were breaking on the housing

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Ayuh,... I'm not overly surprised, as boats, 'n Corrosion go together...

Re: 3.0l not charging battery

I got my new alternator installed and it is charging good and running smooth. Reading 14.4 volts at the battery and 14.6 at the alternator. Took it out last night and it is running good. The only problem we had was the engine harness rattled itself loose because i had pulled it to check for corrosion.

Thanks again for the help!