743 Diesel - hot alternator

[68camaro]

Ok, forgive me if I've missed something via the search and I'll have to find the paragraph setting... The machine was used very little until recently and was one of those $1,500 buys and later learned a starter and glow plugs were all that were needed to get going. I got tired of jumping/charging the battery...the old alt had the two post male/female standard plug in, however one post was broken in the alt and the wire end was so plugged with crap it wouldn't have mattered. Purchased a new one wire alt and ran the one wire to the + on the battery. The thing seemed to be pushing about 11 but not that's not right. It also heated up to where I thought it may catch fire. I bring that one back thinking it was a fluke but we put the new new one on and things started out okay but then it too started to do the same thing. This one seemed to push (est) 12-13 volts like it should but soon got hot and we shut it down. I'm not sure where to start looking. It is an old machine with more than a few cut/taped off wires and the only gauges that are working or hooked up is the volt meter. There's no lights, hr mtr, temp etc. Could something be shorting on one of the misc cut wires hanging around? The ones there are either taped and/or not touching anything. Must we have the alt with the plug-in? Thank you in advance! Regards, Scott

 

[flyerdan]

A butchered up wiring harness could be part of the problem. How hot are we talking here, hot enough to smell, feels like a red stove burner when you put your hand near it? They shouldn't be any hotter than any other part of the engine. If the volts seem okay, it could be producing full amps all the time, which could cause it to heat up. That would be due to a big draw somewhere.
There is a good book for the 743 series in the manual thread, it has comprehensive wiring diagrams that should help you get some of the problems sorted.

 

[68camaro]

A butchered up wiring harness could be part of the problem. How hot are we talking here, hot enough to smell, feels like a red stove burner when you put your hand near it? They shouldn't be any hotter than any other part of the engine. If the volts seem okay, it could be producing full amps all the time, which could cause it to heat up. That would be due to a big draw somewhere.
There is a good book for the 743 series in the manual thread, it has comprehensive wiring diagrams that should help you get some of the problems sorted.

Okay, I'll check it out. It was a hot you could smell from a distance and it started to smoke a little. Certainly way too hot to touch. Thank you for the reply!

 

[foton]

Okay, I'll check it out. It was a hot you could smell from a distance and it started to smoke a little. Certainly way too hot to touch. Thank you for the reply!

if your 743 has a amp gauge what does it read?(with a single wire alt. it might not work right) I think the only reason a alt. would run hot is it is trying to provide all the amps it thinks is being demanded. If you have a spare amp gauge wire it temp. to the single wire to the alt. after it is running look at the amps that the alt. is putting out and trace where the amps are going . Look for wrong amp fuses that have been added or bypassed to provide power vs. fixing it right. the volts might look low if the amp demand is real high too. there has to be wire getting hot as the alt. may be feel around and follow your nose.

 

[Hotrod1830]

if your 743 has a amp gauge what does it read?(with a single wire alt. it might not work right) I think the only reason a alt. would run hot is it is trying to provide all the amps it thinks is being demanded. If you have a spare amp gauge wire it temp. to the single wire to the alt. after it is running look at the amps that the alt. is putting out and trace where the amps are going . Look for wrong amp fuses that have been added or bypassed to provide power vs. fixing it right. the volts might look low if the amp demand is real high too. there has to be wire getting hot as the alt. may be feel around and follow your nose.

usually the only things that can suck that many amps and cause a alternator to overwork is a sulfated battery, or glow plugs that are hot at all time. U&se a test light and see if the glow plugs have voltage while running. If they do, check the relay and wiring.