boat alternator

[Seadoobuddy]

Off a 1991 Glastron with a I/O Merc.
This wasn't charging the battery so I took it to a shop on Saturday. Someone tested it and sometimes it was charging but mostly it wasn't. I was next to him while testing it. The rebuild guy will be back on Monday
I called today to inquire about it and the "rebuild" guy, Kevin, said it's cheaper to buy a new one then replace all the parts in the OEM one.....I'm puzzled about that. He stated once he buy all the parts and installs them it will be more costly. I asked how much for a new one....about $180...I asked what brand and country it's from....He didn't know the country and gave me an off brand name that i didn't understand. I told him to find out what's wrong then call me.

I can't believe that a rebuild kit is more than $180....he's got to be kidding ...right?????

Mine has the voltage reg attached to the back of the alternator.

Should I just pick it up and take it some place else?

 

[Sportster-2001-951C-Stock]

Generally, by the time he rebuilds your alternator including labor it will likely cost as much as a reman unit. Probably the best place to have this done is by an alternator/starter shop although they can be nearly as rare as hens teeth, they're out there rebuilding starters and alternators on heavy industrial equipment every day of the week and have the equipment to test them in every aspect imaginable.

External rectifier bridge? Yours could be the GM CS144 type.

alternatorpartscom sells marine alternators and alternator rebuild kits. I typically rebuild these myself, for my own peace of mind.

 

[CReynoldsMIZ]

I have never rebuilt an alternator, although i have never replaced one on a boat, i have replaced many on cars. I usually just get the cheapest one and at my local store most of them have lifetime warranty's so its a win win

 

[Seadoobuddy]

SOLUTION:

The voltage regulator was bad. Replacement, testing and attaching back on was $60.

But now after I installed it, the Alt. is getting very, very hot to the touch (pulley too). My neighbor brought over his heat sensor gun and it read 162F on the casing of the alt. i called the shop and he said if the battery was low on voltage the alt might be trying to recharge it at full amperage (55 or 60??) and causing it to be hot.
The battery volt on its own was 12.2 or so......while running it was charging at a steady 14.44 V . I put the battery on a 2 amp charge for 2 hrs (had to go to airport) removed the charger and checked, it was 13.2......got home almost 2 hrs later and it was down to 12.6. I'll test it again in the morning and if it's down again guess I'll get load tested and probably get a new battery. I bought this one during the season of 2010. Deka brand.
Would charging it over a longer period help this issue?

any thoughts?????......

 

[Sportster-2001-951C-Stock]

Throw it on an automatic charger and you can leave it on overnight.

 

[Seadoobuddy]

I left it on a 2 amp charger overnight. I took it off at 8:45am and checked it. Meter read 13.5V, read it again at 9:30am , read 13.2V, read it again at 9:55am says 12.85 V.
Will it keep going to down to a certain voltage then stop or is this battery done? it's now 9:57am.

My guess is that it's done, dead, dud, kaput


****EDIT*****
I just called the battery shop and he said the voltage will settle down to about 12.5 -12.6 after the plates cool off. If it fall below that then replace it.
It's still at 12.85V

 

[Seadoobuddy]

I put the battery in the boat and started it.
It's charging at 14.66V and the alt. is not getting hot.

So it looks like the time being it's working just fine.

 

[Sportster-2001-951C-Stock]

Alternators do tend to get warm while charging, not unusual to be hot to the touch, even too hot to keep your hand on sometimes. A shorted cell in a battery can cause this too, less than 12.5 volts is where I call a battery done for after charging and sittiing static for 24 hrs. Anything lower, and one cell is shorted.

2 amp setting overnight should not have overcharged it, many batteries die an early death due to being overcharged on chargers, 24hrs on 2amp setting and it should be fully charged, maybe a bit overcharged.

I use the auto setting at the high rate to bring them up overnight then switch to 2Amps setting and it should begin cycling, the longer the cycle the better but is charged if it cycles on 2A setting. Cycling on 2a rate tells me it's ready for static test.

This is for large batteries, 400CCA or more, on up to 1000CCA I usually buy the 1000CCA units.