altenator got hot and then smoke

[newtoboat101]

mercruiser 5.0 lx 1988 OB794236 got a boat for cheap and now i know why ,but how can i fix this hooked up battery,and altenator got hot and then smoked ,turned batt back off (perko), tried different battery same thing ,are these batteries now bad ,is my perko bad ,is my wiring and alt fried now ,motor has points ,is coil fried have not found any bad fuses yet, how far should my 50 amp circuit breaker stickout to no it not working or how far in to no it works ,unfortunatly the first time we hooked up i tried to start ,and saw trim gauge pin to left,checked fuse ,looked okay,if i get a new alt and batt,and not wiring harness to hook up can i end up do the same thing all over what else could be damaged can i take my alt to auto place and have them test,also should i have starter tested so many question do not no where to start,,i think the person i got it from crossed pos and neg ,and then bailed on it ,so i do so much want to get this running

 

[Scott Danforth]

welcome aboard.

sounds like you have the battery connections reversed. my guess is your alternator is junk now. at a minimum take it in and have it rebuilt (put the magic smoke back in it)

 

[Silvertip]

No need to run out and buy new batteries as they are very likely ok.

 

[newtoboat101]

ok thanx silvertip ,i think the one i just got from walmart ,i will return and get another ,under warranty so why not, but why does that alt get so hot so quick ,can't even try to start ,motr to see if starter or coil or anything else is scorched

 

[newtoboat101]

will take alt to have checked today already pulled out ,can i go to auto store to get free check

 

[Scott Danforth]

if there was smoke, assume you fried something. getting it checked at an automotive store is ok, however do not replace the alternator with an automotive unit.

 

[poconojoe]

Check your polarity. It's like a car red +, black -, but some boats have yellow too....that's negative like the black wires.

 

[newtoboat101]

thank you everyone for getting back to me ,went to auto zone had them check alt they were not sure about testing a boat alt ,but they did ,and said they got nothing out of it ,so i have to assume its fried ,and will replace ,but do you think it went any further along that engine wire harness ,like the harness ,or the starter ,or coil or what else, poconojoe ,wiring seems to be wired correctly ,just hope i did not torch the wiring harness ,no way to tell ,is there

 

[newtoboat101]

i will replace with same model12174n-1g

 

[gm280]

I'm a bit confused reading this thread. If you connected up the alternator correctly, then you do have something shorted in that alternator. But that doesn't mean the Perko switch or any battery is bad. The batteries actually did what batteries are supposed to do. And that is supply voltage/current to whatever they are connected too. Now if you connected the batteries backwards, you could have other problems as well. But only you know if you did that or not... I suspect the alternator has the voltage regulator and diode packs toast now. But hopefully the windings are still good... JMHO!

 

[newtoboat101]

sorry for the confusion ,to be honest i purchased the boat ,and the person i bought it from ,now that i think about ,gave me all the receipts for the merc 5.0 he had installed (reman), ,but claimed he couldn't start because batt was dead ,but knowing what i know now ,he must have crossed the batt terminals at sometime ,you know how later on you look back on situation ,and you relise they are not telling you the whole truth ,but now i have got the boat or the problem,i have carefully gone thru each wire its starting point all the way to the end point ,so i am 99 percent sure all wiring is correct ,but feel he crossed batt terminal and burned things up,and left it ,alt for sure not sure of wiring doesn't look burned ,,just electical tape alittle melted in one spot but not wires took tape off wiring harness and checked i just have strong feeling he crossed batt wires ,i have seen it in autos ,but fusable link usually protects alt and starter any comments welcome please

 

[lmuss53]

Get a known good battery, hook it up right and see what it does, it may have destroyed everything or nothing at all. They are not the same parts, but this is old school automotive wiring.

Don't trust the color of the cables, they may have been swapped out for some reason somewhere along the line. Make sure the negative wire is going to a ground. I'm not absolutely sure on the hot, but something like the heavy wire going to the hot post of the starter with a branch wire coming from the alternator.

Odds are it fried the alternator but I've seen them survive this and it can be rebuilt or you can get another, I would not expect anything else to be bad but you never know til you try it.

 

[newtoboat101]

thanx all for replies got new alt ordered so i won't know anything maybe a week or more thank you for all your advice ,i will follow up later on iboats

 

[UncleWillie]

In the mean time; Disconnect the Alternator wiring, Charge the battery, And see what works and doesn't.
You do not need an alternator to run the boat.
It will run just fine for as long as the battery lasts, which could be a few hours.

 

[newtoboat101]

uncle willie disconnect all wiring from alt and try to start engine,ok will do ,or should i just check light, pump ,bilge,etc.? ok thanx

 

[UncleWillie]

You can check everything that you wish. The Alternator is essentially just a motor powered battery charger.
You will need to keep all the wires that were originally attached together on the Alternator, still attached together, as if you have an invisible alternator.

You can start the engine normally, don't forget the water.
I would not be comfortable telling you to take it out on a sea trial unless it were an emergency condition.
But Yes! you can run the engine without an alternator for as long as the battery can supply power to the ignition.
The battery lasting a couple of hours is not an unreasonable expectation.
You should realistically be able to tell what else may be malfunctioning in a few minutes.

 

[newtoboat101]

thanx to all who helped ,i used uncle willie 's advice hooked it up without alt wiring hooked up ,and it started ,sound sweet, had muffs on only ran for less than 5 minutes ,shut it down ,could not be any happier ,i paid next to nothing for boat ,and all that seems wrong was altenator ,his loss ,and my gain ,75 bucks for new altenator and i should be able to put in water ,what a relief,thought i had bought a problem ,things are looking up thanx again to all that helped