Generator has two terminals, the  "A" armature and "F" the field.... Think of the "A" as being the output (HOT) and the "F"  field as being the ground..  To bypass the Regulator for a test, you can GROUND the F terminal with a jumper.. See if the amp meter jumps up.. also use a voltmeter to test from "A" to GROUND with the jumper in place.. IF you get 6.7 volts ( 6 volt system) or 14 volts ( 12 v system) then you know the Generator is GOOD and the Regulator is the problem....

Old generators can get worn out brushes or shorted wires inside, or dragging bearings, etc....Everything has to be narrowed down to get things to work. Sometimes getting a rebuilt Generator and a NEW regulator set to match is the best long term solution.

There is a guy STEVE at B&B on this site that can do the work for you if you want a professional, long term fix.

also touching the BAT and GEN terminals together for 1 second will TRAIN an old generator to start charging again.  Some of them "forget" what to do over long periods of time..   

Here are some links to helpful info on generators and voltage regulators.  I have three Gen/VR tractors, and the systems work fine if maintained properly. 

https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ac&th=92006" rel="nofollow - WD Generator Question - Yesterday's Tractors (yesterdaystractors.com)

https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=nboard&th=436116" rel="nofollow - 8n will not charge battery - Yesterday's Tractors (yesterdaystractors.com)

http://www.southernwheels.com/March-07.htm" rel="nofollow - March-07 (southernwheels.com)

https://www.yesterdaystractors.com/articles/artint29.htm" rel="nofollow - Yesterday's Tractors - Two-Brush Generators (yesterdaystractors.com)

http://www.bowersflybaby.com/tech/delco_remy_generator.pdf" rel="nofollow - delco_remy_generator.pdf (bowersflybaby.com)

There are also several "experts" on this Forum and numerous discussions over the years on the Gen/VR topic (try a search)

Lots of YouTubes, many for older cars and garden tractors, on the topic

Some of the top trouble shooting checks would be....

1. clean to shiny all the wire terminals, battery posts, ground connections to the tractor (remove paint and oil where the Gen and VR touch/ground to the tractor

2. Remove the cover of the VR and clean the contacts of both sets of points

Good luck

http://www.ruiter.ca/mc/info/PDFs/1R-116.pdf" rel="nofollow - http://www.ruiter.ca/mc/info/PDFs/1R-116.pdf

After you rebuild the genny, and regulator ,replace 100% of the original wiring ! Over 5-6 DECADES, it's not 'reliable'. Wires corrode, connectors corrode, screws corrode,......

it's an age 'thing'.

Take them to someone who really KNOWS them.  After 60 years, many of these generators have not seen any maintenance, so neglect is the probably the number 1 reason for their poor performance.  I take mine to a local starter and alternator repair shop.  They do a thorough cleaning, replace and adjust the brushes, replace the bearings and lubricate everything.  They also load test them to make sure they are working properly.  It will come back as good as new.  Have them provide you with a new voltage regulator as well.  Most of the time, that is all these things need to work again.

I had one on my D17 diesel which worked sporadically, but after they replaced the armature, it works amazing every time. 

I have 12 tractors with generators.  After getting it professionally rebuilt, rarely do I have to touch the generator again.  Any subsequent problems usually are with the voltage regulators that are cheaply made these days.

Great info sources from all the guys.  When rebuilding old Generators, they need to be completely gutted, new Armatures put in them along with all the components that make up the unit. From there, as Steve mentioned the correct Voltage Regulator needs to be mated to the unit and set up properly. I've been rebuilding these units for over 50 years. Every Gennie that comes in my shop gets the "full treatment". The unit then gets a VR mated to it and run on the 881 machine to dial it in.  Once its done its ready for service. The unit is basically brand new inside, and is ready for many, many years of service providing the wiring system that works with it is in tip top shape! People forget. You can have a real nice rebuilt Generator, but its only going to work as good as the system it connected too! Make sure the wiring system is just as good and you won't have any troubles. In most cases if the wiring system is original, that should be replaced as well not knowing how many Gremblins can be in a 60+ year old system. This includes the Battery & Battery cables as well whether 6V or 12V system.   Thanks for the mention Steve!

Steve@B&B

Just trying to be helpful.........this Thread started out with a request for info on generator/VR repair and maintenance.  The responses from Forum members has been excellent.

However, there does not seem to be any feedback/update on how the originating problem/issue turned out, was it resolved, not solved, still an issue?

The issue was raised last June, and rebooted today with continuation of excellent help postings

I am just flagging the status of the Thread situation here, and hopefully the need for info/help has been resolved

I think a lot of the problems with MECHANICAL Regulators is buying the WRONG one.. If you have an old farm tractor , you need a regulator that can work at 8-9 amps Total... Many of the "auto" regulators were 30- 35 amps... That is not "ideal" for a farm tractor.

My solid state VR for the D17 was from Clover Systems, a model DR110.  I put it on in 2014, and they may not be in business anymore.  However, many of the vintage car forums have similar generator systems, and have references to other more current vendors. 

Edited:

Here is their website:

https://cloversystems.designscience.info/products/legacy-products/dynamo-regulator-2/" rel="nofollow - https://cloversystems.designscience.info/products/legacy-products/dynamo-regulator-2/

Edit#2:

Oops!  Looks like they are no longer in business, but left their website up.

Steve is correct again. Two things people do wrong with Generators. First, they don't mate the correct VR with the unit. "Universal" VR's are BS and incorrect to start off with. You need to mate the correct VR with the units output and dial the two together on an 881 machine or equiv.  Second problem people do not do with VR's is make sure they are grounded!! If you just had the Generator or the Tractor all painted nice, paint makes a good insulator and the VR will NOT be grounded. I always tell our customer's to run a ground wire from the VR's chassis to the Battery ground. This insures the VR's chassis is grounded so it will work correctly or just work period.

Steve@B&B

If you look at the procession of this thread, you'll see that it went dormant in June of last year.

The reason why it was restarted, was due to a spammer's necropost.