Well.....things happen. Was getting my boat lake ready and installed the battery. The previous owner had some mickey mouse wiring he did to install the radio and depth finder. Thought I had it all figured out...NOT. Hooked the negative to the positive, this is my boat, but it's a 3.0 GM engine. I turned on the master switch and noticed the negative spark, then heard a faint sound, I immediately turned off the master switch. It was on for maybe 4 seconds. I then noticed and smelled smoke coming off the alternator. Kraph….after I regained my composure, I followed all the lines and got them connected the right way. Kept my fingers crossed and all gages worked, hydraulic pump worked, bumped the starter, it works. Hooked it up to the water muffs and engine cranked. No smoke or anything coming off the alternator. Noticed the volt meter was showing 13 volts. When I turn on the blower or some other aux unit, volt meter would dip down a little, as it normally does. When I rev the engine, volts go up. It's like nothing ever happened. I don't get it. I didn't have my volt meter with me to confirm the alternator output, but have no reason to believe that it's not off that much. This is a factory installed AC Delco marine alternator, 1996. Have never had problems before. Noticed the starter cable got hot, but nothing melted or fried. Can I trust it? Seems weird that something smoked and it works fine.
Reversed battery cables
- Thread starter Schmoe
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Sounds like you let out the brown smoke, not the blue smoke. Everybody knows that letting out the blue smoke is what kills electronics. All is well.
On a more serious note, it sounds like you might have overheated wire insulation. Perhaps alternator diodes reversed from what was intended effectively grounded your battery through the alternator. Connection wires and alternator core wire then overheated, causing the smoke. From the sounds of things, it doesn't seem like you broke it.
Can you trust it? Parts wear out and boats break down all the time. If you are crossing the Atlantic, I would vote no, and I'd want to take tools and a spare. If pleasure boating in a medium sized lake where your battery will provide enough juice to get you to shore in the event of an alternator failure, I'd say yes.
On a more serious note, it sounds like you might have overheated wire insulation. Perhaps alternator diodes reversed from what was intended effectively grounded your battery through the alternator. Connection wires and alternator core wire then overheated, causing the smoke. From the sounds of things, it doesn't seem like you broke it.
Can you trust it? Parts wear out and boats break down all the time. If you are crossing the Atlantic, I would vote no, and I'd want to take tools and a spare. If pleasure boating in a medium sized lake where your battery will provide enough juice to get you to shore in the event of an alternator failure, I'd say yes.
You don't plan on shutting the engine off in the middle of a lake do you?
Kind of what i was thinking, don't turn off motor until I'm at a safe place, or take a smaller back up battery. Getting that alternator out is easy, lots of room to work on it. I took a boat load, get it...lol, of pictures of it so i can see the how it all goes together. With the age of that boat, not too mad about getting another alternator because at some point, going to have to start replacing parts.
Assuming it works that long, take it out this winter and have it rebuilt.
Rock it till the prop falls off.......or something goes wrong. All's well that runs well.
There are 6 diodes in the bridge. Its 3 phase. Maybe one was fried. There are meters that will tell you it the alternator is putting out the proper kind of DC, as will an oscilloscope.
Renew your SeaTow membership.
Renew your SeaTow membership.
Using a multimeter you can check the alternator. Set the multi meter on ac millivolts. With the engine running place red probe on alternator output, black to ground. If the reading is above 400 millivolts(0.4 vac) the alternator is no good. This is called ripple. You want as close to zero as possible. This test diodes and capacitors on the alternator. I suspect the smoke was a capacitor, that's why it still works.
Take it yo he old DC motor repair shop when seasons over. Don't trade in or buy new you'll get robbed. Till then keep an eye on the ammeter and enjoy. Or do what I do when I'm questioning a boat battey, take another along with a set of jumper cables.
Or if you're the nervous sort yank it now and see he old DC motor shop . He can test it on the spot and tell you if it's ok. I haven't bought an alternator or starter since the 80s using my guy and never spent over $75
Or if you're the nervous sort yank it now and see he old DC motor shop . He can test it on the spot and tell you if it's ok. I haven't bought an alternator or starter since the 80s using my guy and never spent over $75
Those boat cables can get confusing on many. Especially with shut offs dual batteries and multiple grounds sometimes.I solved that on mine 20 years ago simple and cheap.
Just take a small paint brush and paint the end 4-6" with red paint. It isn't pretty as some flakes off but enough remains to do the job and you can always add more later. Nobody sees it anyways so pretty isn't a factor. Colored tape or large heat shrink works too but the terminal is too fat to stretch over and shrink down well . It works well if you put it on before the terminal goes on though.
Just take a small paint brush and paint the end 4-6" with red paint. It isn't pretty as some flakes off but enough remains to do the job and you can always add more later. Nobody sees it anyways so pretty isn't a factor. Colored tape or large heat shrink works too but the terminal is too fat to stretch over and shrink down well . It works well if you put it on before the terminal goes on though.
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