Faulty battery, bad alternator, or both (photos)
Don't get too "fussy" with your meter. Analog meters may be off a bit. A "fully charged" "lead acid" battery is nominally 12.6V. Your meter might read anywhere from 12.2--12.8, let's say, and be "OK" for "that meter.
BUT it is NOT charging.
Here's a simplified diagram of your VR / alternator:
NOTICE that power comes from the "key", goes down and feeds the ballast resistor for the ignition
..........branches off from there and feeds the "I" terminal on the regulator..........
as well as one of the two field connectors on the alternator. This is normally blue or light blue at the alternator
THIS BLUE FIELD wire should be "same as battery" with the key "in run" and engine stopped.
Remove the green field wire. Take a clip lead and hook to the alternator field terminal which you just unhooked. With the key in "run" ground the wire. In subdued light, you should see a small spark
Start the engine and slowly bring up RPM. It should charge. If not..........
go out and hook your meter to the alternator output stud. Check voltage while varying engine RPM
Very high......above 14V and way higher than battery.........means you have a break in the output line between alternator and battery
Very low, below 12.6 means it is NOT charging.
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If the above test DOES result in the ammeter showing a charge, now you either have a problem in the field wiring, bad regulator plug, UNgrounded regulator, or bad regulator
THE REGULATOR MUST BE grounded. Remove it, scrape it clean, and remount using star lock washers. The bolts MUST be tight.
WIGGLE the VR connector.
CHECK the wiring. One way to do this is to............
Remove the blue alternator field wire and ground that alternator terminal. Remove the VR connector. jumper between the two terminals. Run the engine and see if it charges. If so, the wiring is good. Again, suspect poor connections at the VR connector.
If you check all the above, and everything seems OK, replace the VR
Don't get too "fussy" with your meter. Analog meters may be off a bit. A "fully charged" "lead acid" battery is nominally 12.6V. Your meter might read anywhere from 12.2--12.8, let's say, and be "OK" for "that meter.
BUT it is NOT charging.
Here's a simplified diagram of your VR / alternator:
NOTICE that power comes from the "key", goes down and feeds the ballast resistor for the ignition
..........branches off from there and feeds the "I" terminal on the regulator..........
as well as one of the two field connectors on the alternator. This is normally blue or light blue at the alternator
THIS BLUE FIELD wire should be "same as battery" with the key "in run" and engine stopped.
Remove the green field wire. Take a clip lead and hook to the alternator field terminal which you just unhooked. With the key in "run" ground the wire. In subdued light, you should see a small spark
Start the engine and slowly bring up RPM. It should charge. If not..........
go out and hook your meter to the alternator output stud. Check voltage while varying engine RPM
Very high......above 14V and way higher than battery.........means you have a break in the output line between alternator and battery
Very low, below 12.6 means it is NOT charging.
========================
If the above test DOES result in the ammeter showing a charge, now you either have a problem in the field wiring, bad regulator plug, UNgrounded regulator, or bad regulator
THE REGULATOR MUST BE grounded. Remove it, scrape it clean, and remount using star lock washers. The bolts MUST be tight.
WIGGLE the VR connector.
CHECK the wiring. One way to do this is to............
Remove the blue alternator field wire and ground that alternator terminal. Remove the VR connector. jumper between the two terminals. Run the engine and see if it charges. If so, the wiring is good. Again, suspect poor connections at the VR connector.
If you check all the above, and everything seems OK, replace the VR