Alternator heating up and belt squealing...

[sheltonchris1]

Ok, here is what I have
A 1986 Ebko Bowrider with a Mercruiser 5.7L V8 260 motor.

Here is the problem:
When I crank up my boat, the alternator immediately begins to heat up causing the belt on the alternator to squeal. I was told this could be caused by a short somewhere in the wiring system. Here is the catch, it doesn't do it all the time. In fact, we ran the boat all weekend without one problem and then today I went to crank it up and again the alternator starting heating up. The belt squealing is actually a good thing in a way because it is an indication that the alternator is heating up. I have looking around for the short, but as you can imagine its not exactly an easy thing to pinpoint.

If anyone has any suggestions as to where to look I would appreciate it. I'm really ready to resolve this problem so that we can get on with boating without being concerned that the boat won't be usable at some point because of the short, if in fact that is the problem. Thanks in advance for the help.
Chris

 

[JustJason]

Re: Alternator heating up and belt squealing...

do you have wing nuts on your battery?

 

[sheltonchris1]

Re: Alternator heating up and belt squealing...

No, I just have regular nuts on the battery.

 

[Don S]

Re: Alternator heating up and belt squealing...

If batteries are going bad, or very low, the alternator WILL charge a lot. And they will get hot.
Loose/worn belts on rusty pulleys causes squeeling.

 

[sheltonchris1]

Re: Alternator heating up and belt squealing...

The battery is actually new so I don't think the alternator is over charging...is there a way to test to make sure the alternator is not over charging? Plus the belt only squeels when the alternator is getting hot.

 

[Don S]

Re: Alternator heating up and belt squealing...

A voltmeter on the battery would be a good start. Don't use the dash voltmeter, a DVM is what you need if you want to test things.

 

[sheltonchris1]

Re: Alternator heating up and belt squealing...

So what will the battery read if it is bad?

 

[Don S]

Re: Alternator heating up and belt squealing...

To test a battery, you need a hydrometer and a load test.
Putting the DVM on the battery tells you what the alternater is doing.

 

[sheltonchris1]

Re: Alternator heating up and belt squealing...

Ok, I will be taking the battery tomorrow to be tested just to be sure that is not causing the problem. Now, in the event that the battery is fine. What should be my next course of action. I have been working with this motor for a bit now and have gotten pretty familiar with it. I have checked most of the ground points that the manual shows in the wiring diagrams and there doesn't seem to be an issue with that. I guess my biggest curiosity is that the problem is sporadic, it would seem to me that should help narrow down what problem I am having.

 

[fuzzybob]

Re: Alternator heating up and belt squealing...

Take the belt off and check the shaft.... turn smooth, can you wiggle it???

 

[rbh]

Re: Alternator heating up and belt squealing...

there is a difference between short and load.
short is when positive goes to ground with no resistance, load is the power draw.
and the other thing you should look for is belt tension and you have the rite belt for the application, is the pulleys on the alternator and the crank the same size for the belt?
rob

 

[Evinrude Boater]

Re: Alternator heating up and belt squealing...

See my recent post about sqealing belts. It can cause more problems.

 

[sheltonchris1]

Re: Alternator heating up and belt squealing...

Ok, I had the battery tested just to be sure it was in good shape and it is. When you say check the shaft, are you talking about on the alternator? The belt is the right one for the application. I'm assuming the power draw is right because when the boat is on, we read on the battery directly around 13v. Still hoping someone has the answer to this problem.

 

[sheltonchris1]

Re: Alternator heating up and belt squealing...

The alternator is also a very new peice of equipment that I put on the boat toward the end of Spring 09'. I also took it to an alternator shop to have it tested and it is in good shape. It is a 4 wire alternator, orange, black, purple, and red. I can't say that I have ruled out the possibility of all wiring being ok because there is alot of wiring in the mix. When you say it glazed the surface and it will have to be replaced are you speaking of the belt or alternator.

Let me give you guys a time line to paint a little better picture.
Feburary: lifted the motor and replaced some gaskets, starter, and oiled everything up
April: replaced alternator
April: replaced battery
May: replaced fuse on starter solenoid.
Alternator giving me problems with heating up and ended up having to replace the belt.
Had all these tested once again to make sure I wasn't sold a bad part
June: replaced belt on alternator and power steering
June: all seemed well, alternator stopped heating up, no belt squeel everything perfect
Beginning of July: Ran great, then out of no where the belt squeeled and the alternator starting heating up again. (when I say heating up I mean that I burned my arm on it once)
Then everything was fine when I turned off the boat and turned back on. Ran the boat all weekend about 15 hours without a single problem. Then yesterday belt squeel and alternator heat up, today the same thing.

As you can see this is becoming alittle frustrating because it is kind of a sporatic problem. I hope these details kind of clear up some of the confusion on the problem. Thanks in advance.

Chris

 

[rockyman]

Re: Alternator heating up and belt squealing...

if it were me brfore i beat myself to much over this i would exchange the alternator you just put on there because they work different when they have pressure on them as opposed to just letting a shop just spin it around and say yes its good, all that does is just tell you if thing is putting out what its supposed to put out or not.but when you put the belt back on your problem starts all over again.the shaft in the alternator could be bent slightly a bearing in there could be bad ,im not a mechanic per say but i have handled a few altenators in the past. just a thought .

 

[sheltonchris1]

Re: Alternator heating up and belt squealing...

I do have a amp meter and it is ready 13v. I have decided to go ahead and let me mechanic take a look at it tomorrow. Maybe he can figure out the problem. If so, I will post it so that everyone can have a chance to see what it was. It could definitely be the voltage regulator, but I will let him figure it out. Thanks for the help!
Chris