How can I tell what I have. I do not see any numbers on it.

 

That looks like a 100% stock 6V generator. The flip cap for oiling on the aluminum rear cover show that it came with a rear bushing.

 

Roger that

 

Is there a way to test the output voltage? The truck has several 12V lights and a 12V battery, which seems to be working fine... knock on wood.

 

You can tell if it is putting out 12V by placing a DC scale meter across the battery with the truck running above idle, 1000 RPM or higher. If it is 12 V, converted or other wise, the reading will be be 13-14 volts. Any voltage less than 12 volts, the generator system is not producing 12V.

 

Yes, search "full fielding" a generator.

Remember the open circuit voltage will drop quite a bit under load though, a DVM is going to read "high" with no load. In cold weather the internal resistance of a battery is a lot higher. Even at 80F we want to see a couple volts more than the open circuit voltage of a fully charged battery, in the case of a "6 volt" system somewhere around 8.3 - 8.5 with the battery hooked up, at say 1500 RPM. Make sure all your grounds - generator brackets to block, and cable connections are spotless.

 

With or without the 12V battery hooked up, would I take my voltage reading? It's been running like this since I've had it. The headlights were 12V and the tail lights are 12V since before I got it.

 

7.0 - 7.2 is the control voltage for 6v
13.8 - 14.0 for 12v

 

If it has been running like this for any time, the chances are pretty good it has been converted to 12v. A 12 battery in good condition, unhooked or in an inactive, non charging circuit will read a fraction over 12V. If the generator and regulator are working at 12V the active, running, voltage across the battery will be [B]more than 12V. The generator system, if working, will always produce more than the static 12 V. The headlights being 12V is a pretty darn good indication that the system is running 12v.[/B]

 

Yeah, it's a moving target depending on temperature, load and level of charge. Those figures sound a bit low, imo.

15.1 at 50F for example, is spec for 12 volt system. A battery approaches a full charge only at approx. 2 volts over the resting open circuit voltage. It's also a balance between excessive current, and not boiling out the electrolyte. Generators were replaced for some good reasons.

 

OK... so what happens if it's a 6V generator, 12V battery, 12V coil and 12V head/tail lights?

I assume the regulator is 6V unless it's been changed???

I have a feeling that someone was trying to upgrade it but it was never finished. The dash lights are dead and it has a 6V flasher.

Do I finish the 12V conversion or go back to 6V?

 

It's a 12V regulator.

 

A 6v generator will put out 12v if hooked up to a 12v regulator, but will only put out about 25 amps.

If the truck has been running and starting fine, just finish off the conversion, less than $10 of parts needed.

 

13.6V, so it is a 12V generator

 

Been meaning to ask - my truck regulator is like the one pictured. There was at one time, a plastic snap on insulator that covered the terminals. Does anybody offer those as a repro or something?