Wiring/Alternator Short?

[goinhungry]

I have a 1989, Merc. 3.0, 4 cyl I/O that I lent to a friend to use for the day. He brought it back shot, and since I wasn't there I unfortunately can't give any more info. than he relayed/what I observed. When the battery was hooked-up it got hot at the terminals, but he took it out/ran it anyway. While running it the alernator frame (mando) came apart, and the bolts holding it together slipped out,sheering off the fins as it spun. The boat died so he was towed. I had the alernator re-built, put in a new battery, and reinstalled the alternator. All the wires are hooked up properly, as are the battery connections. Now, when I start the boat and run it, the alternator starts smelling, and the terminals start getting hot. I was very <br />careful to only do this for a few seconds, as I wanted to test everything out, and make sure I wasn't toasting the alternator. I checked the wiring, and everything appeared ok, but there was a loose wire in the key switch, which I re-tighted (it's a bolt-on). It's curious becuase it only does it when it's running/cranking, not when I just have the key clicked on in the first position. To top it all off, the shaft from the engine that turns the belt for the alternator/water pump isn't spinning when the engine is running now, and it looks like <br />there's oil in the bilge - could he have blown the engine and/or drive shaft too? I used the boat a few times earlier this season myself, and <br />didn't have any problems... Any help/ideas are greatly appreciated!!! <br />Thanks.

 

[rbezdon]

Re: Wiring/Alternator Short?

As some one on this site always says, two things you NEVER lend out, your boat and your wife because they will both come back with a rod thrown in them!!<br /><br />Sounds like the field or stator winding in the alternator is shorted, more likely stator. This is not common to replace in a rebuild either so it may be bad despite the rebuild. I would scrap the whole thing and get a new one. As for the alternator causing the engine to blow, I doubt it. I dont understand how what you are saying could happening. The pully on the shaft the drive the water pump and alternator is usually attached to the crank shaft and if that is not turning, the engine cant be running.

 

[Haut Medoc]

Re: Wiring/Alternator Short?

Ron, I was trying to figure that one out myself! ....JK

 

[fisherman73]

Re: Wiring/Alternator Short?

Unless when the alternator failed it siezed up and broke the damper rubber or loosened the pulley.

 

[rbezdon]

Re: Wiring/Alternator Short?

fish, I am sure that would have smoked the belt first. That dampner is pretty tough and with the difference in pulley size there is just no way the belt would slip on the balancer and grip on the tiny alt pulley long enough to smoke the balancer. The size of the pulleys are such that is the alt siezed the belt would continue to grip the balancer pulley, slip an the alt pulley and go up in smoke fast.

 

[Haut Medoc]

Re: Wiring/Alternator Short?

That is possible....The pulley is bolted right to that.....The pulley is bolted on, so I don't think it's a loose pulley. Loosen the belts & see if you can turn the pulley by hand. If you can then that's your answer.....JK

 

[goinhungry]

Re: Wiring/Alternator Short?

Thanks everyone. Great ideas. I did try loosening the belt when I first noticed that the shaft wasn't spinning, and even though it was loose enough that I could turn it by hand, the shaft still wouldn't turn. Any other ideas? <br /><br />Also, does anyone feel that the smoking alternator/hot leads could be caused by anything else besides the alternator? I'd like to try to troubleshoot/elminate every other possibility before bringing it back to the alternator shop - Thanks again for all the insightful advice!

 

[goinhungry]

Re: Wiring/Alternator Short?

Besides, even if the belt wasn't spinning, it shouldn't cause smoke/overheating of the alternator/battery, should it? Wouldn't it kinda be similar to when your alt. belt breaks on a car, and the battery just powers the plugs 'til there's no juice left, and then you're stuck on the side of the road starring down at where a belt used to be.... The fact that it's smoking tells me there's a bad wire/short somewhere. Would a loose wire at the switch ever possibly cause something like this, or sould I start elsewhere? Thanks

 

[rbezdon]

Re: Wiring/Alternator Short?

Hungry, something is just not connecting for me. If the shaft driving the belt for the water pump and alternator isnt turning, the engine isnt running or cranking. Even loosening the belt I wouldnt expect you could turn it by hand. That is why you need a starter motor to turn it over. And the answer is no, the alternator can not get oil in the bilge. Lastly, I would get a new alternator and battery in there and see where your at. I am sure your alternator is toast, the regulator is likely toast (it is inside the alternator) and running the engine that way toasted the battery if you saw it smoking. Get all the wires connected up properly before trying the new ones too.

 

[Haut Medoc]

Re: Wiring/Alternator Short?

If you can turn the pulley that sits in front of the crankshaft by hand, the damper is shot. With the belts loose, it should turn anyway, when cranked, just like a prop with a bad hub....Jk

 

[goinhungry]

Re: Wiring/Alternator Short?

vatter, so if I can turn it over by hand, then wouldn't that mean that there is probably a greater problem other than just the alt./wires, and could possibly be the crank shaft/dampner? I wouldn't want to put in another (3rd) alternator if there's a problem causing burnouts. Also, even though the crank at the belt isn't spinning, the prop is - it there a union or something that could have sheared? If the damper's shot, would that cause oil to leak out? I'm just kinda on the line right now, and if I need a new alternator, new battery, new dampner/crankshaft, neew head gasket, etc., etc., I may just take this boat out behind the barn and put it out of its misery...

 

[rbezdon]

Re: Wiring/Alternator Short?

If the dampner is bad, the belts wont turn to turn the alternator so a bad dampner will not burn out your alternator. If you can turn the belts by hand with them tight as they would normally, something is wrong. A dampner is a steel ring that is mounted to a rubber material which is on a steel core. There is usually a pulley mounted to the steel core with three bolts. If it had happened that the rubber deteriorates and the outer ring can slip on the steel core. But since the drive pulleys are usually screwed to the core with the three bolts a damaged dampner rubber or "spun" dampner usually will not result in the belts not being driven properly. If the shaft the dampner is on (and hence the drive pulleys) is not turning and the prop is, you have a broken crankshaft and the engine will not run. I suspect this is not the case and you are missing something. Since you have burned out three alternators, I suspect you still have something damaged in the electrical system. There is no way the alternator issue is being caused by a bad head gasket, broken crank or damaged dampner. There is no reason to "shoot the boat". What I suggest is that you take it to someone who understands the system. It is obvious that wiring it wrong has expanded the original problem quite a bit and with out a deeper understanding of some of the terms and issues, the problem is not going to get completely fixed.

 

[goinhungry]

Re: Wiring/Alternator Short?

Thanks Ron.

 

[Bt Doctur]

Re: Wiring/Alternator Short?

Wondering if the keyway on the balancer sheared or if the nose bolt sheared too? Only way i know of to run the engine and not turn the harmonic balancer.

 

[rbezdon]

Re: Wiring/Alternator Short?

Bt Doc, still wouldnt burn the alternator. Gotta be a lot more to the picture.

 

[Dunaruna]

Re: Wiring/Alternator Short?

If it were me, I'd be turning my attention to the starter solenoid - looking for a short.

 

[goinhungry]

Re: Wiring/Alternator Short?

Ron- I think you're right in that there's more to the picture - I think there is definitely more than one problem, and they aren't necessarily related/causing the other. I think he probably ran it too hard, and when the alternator seperated and came apart he kept running (even though he could hear the alternator finns being sheered off) and while the alternator's sizzling it's probably causing shorts and burning wires or other items out (like a starter solenoid maybe) and then when it's completely torqued to the side it causes the dampner,keyway, balancer and/or drive shaft. So even though it all happened at the same time, I now have several problems to fix, so of which are, and some of which aren't related. Dunaruna, would a short in the starter solenoid continue to produce heat even when it's running and no longer cranking?

 

[rbezdon]

Re: Wiring/Alternator Short?

Hungry, it depends on where the short is if one exists. It is more likely the it would not continue but it is remotely possible.

 

[goinhungry]

Re: Wiring/Alternator Short?

does anyone know if there are ways to test the starter or alternator while it's on the boat, without cranking it over, to determine if there's a short in either of them? I don't want to run it if it's going to worsen the problem, but don't know if there's any way to do it? Any advice appreciated! Thanks.

 

[Dunaruna]

Re: Wiring/Alternator Short?

Read this - <br /><br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=011396#000006