Low voltage?

[vtach]

I have a deuce that the voltage meter seems to drop over time. One time it was no longer reading and my headlights were very dim. Found a small wire that was pinched on the alternator cap (was ground out and sparking). I repaired it, charged the batteries and all was good for a few days. Now the vo;t gauge is droping again.
I hooked a volt meter up to the alternator and both the small and large wire are putting out 23.7 volts at 1100 rpm. The truck's volt meter that is reading yellow shows 23.7 volts, and 23.4 with all the lights on. Is this normal?

There are some stray wires under the dash that to be taken care of too.

 

[Boatcarpenter]

That is very low alternator output. Charging voltage on batteries should be 28V +/- 0.2V.
Something is not right.
Check the TM for proper procedure to increase the alt. output.
BC

 

[vtach]

Okay, I wonder if something fried because of the pinched wire? Or would that kill all output?

 

[Josh]

my truck just started doing the same thing, it keep jumping around from 0 volts to 16 and like 22, then to 28, and so on, im taking it off and having me and my buddy are going to tear it down and see if the brushes or what not are messed up

 

[Bill W]

vtach
On the 60amp mil alt , over by the wire hookups there is a small threaded allenhead plug that you remove and then insert a small straight blade screwdriver into a slotted screw which you can turn to raise or lower the regulator output.

 

[avengeusa]

vtach
On the 60amp mil alt , over by the wire hookups there is a small threaded allenhead plug that you remove and then insert a small straight blade screwdriver into a slotted screw which you can turn to raise or lower the regulator output.

yup, try that first

 

[vtach]

Thank you, I will try that tonight. I assume clockwise increases voltage output? Turn it until I reach 28 volts? Should the truck be idleing at any particular speed?

 

[Boatcarpenter]

Under Resources at the top of the page, go to Technical Manuals, find TM 9-2320-361-20 and go to page 2-90. Page has the procedure for testing at various RPM's etc.
I don't want to sound like our departed friend Ace, but RTFM.
BC

 

[vtach]

I have read the TM, and it never states how to adjust the alternator, just says replace.

 

[Boatcarpenter]

Well vtach, I don't know what to say here. You asked about what RPM's to check alt. output at and I found you an answer and then you shoot back a curt answer about another question you asked.
Sorry for trying to help.
BC

 

[Bill W]

Vtach
Unlike generators, Alternators are constant output so I'd say about 700rpms or more to set. I set mine ( on my last deuce also) at 27.5v at idle (750-800rpms) which puts the indicator on the gauge right in the little box thats located in the green zone where they recommend it to be.

 

[vtach]

Boatcarpenter, I did not mean it in a smart way, sorry. I greatly appreciate everyones help here. i just ment that the TM does not give a way to adjust the voltage, just to diagnose a problem. However, I already had the problem nailed to the alternator.

 

[vtach]

Okay so I attached a volt meter to the little wire (586 ?) that shows no voltage when motor is off. Then while idling ~100rom it showed 23.8 I removed the allen plug and turned the adjustment screw quite a bit with no change in voltage in either direction? Any ideas???

 

[vtach]

Well after doing some more checking, the little wire that shows no voltage with engine off, shows 23.92 volts with ACC on, and drops to 23.82 running. When I disconnect the the battery while the engine is running, it shows no voltage anywhere. So this means the alternator is not putting out any voltage.
What now? The alternator looks new. Belts/pulley are turning.
Anyone have an alternator to sell?

 

[avengeusa]

i ave an alternator kit that i sell if you do not have to have an original, i have an ad on the site for it......

 

[vtach]

We replaced the generator and all is fine now. I will be looking for a spare though. Yhanks for everyones help.