1950 john deere late model b electrical help

hello all, i am new here. i am 28 and just bought my first old tractor to restore a 50 john deere late model b . problem is when i shut the tractor off, the ammeter shows i am drawing current. some one in the past took the wires off the voltage regulator. the regulator is a 3 terminal. can anyone tell me what wires are supposed to be connected where, or if this regulator will work. it has a field, generator, and battery terminal. i have read a couple places you need a special light switch for it to work. mine just has a plain toggle switch. they had the field wire on the generator grounded. also the starter turns over very slow, too slow to start the tractor even with a brand new, fully charged battery. (i disconnected the generator to keep if from draining the battery) what might be wrong with the starter. thank you very much for the help........... carl

Okay if when you shut it down she draws a heavy discharge current, the cutout relay (inside of and a part of the Voltage Regulator between its ARM/GEN and BAT terminals) may be sticking closed, in fact if the belt were loosened the genny would sit there and run like the DC motor it is. That will discharge the battery plus make the genny hot. Its supposed to open when the tractor is shut down and close once the genny is turning and is producing sufficient voltage.

The tractor originally had a 4 (NOT 3) terminal Voltage Regulator with BAT LOAD FLD and GEN/ARM terminals with GEN/ARM off on one side or underneath all by itself. They wire:

BAT to load side of ammeter
LOAD feeds hot battery voltage up to the light
switch
FLD wires to gennys FLD post
ARM/GEN wires to gennys ARM post

If its really a 3 wire VR

BAT to load side of ammeter
GEN/ARM to gennys ARM post
FLD to gennys FLD post

On the older systems that used a simple 2 wire Cutout Relay (BAT and GEN) with no 3 or 4 terminal VR, the gennys FLD post wired to a Low/High Charge manual light switch which could be set for low or high charge. On the new systems with a VR the light switch controlled lights only but NOT charge rate.

If she cranks slow Id remove, clean and wire brush and re attach each and every battery and starter and ground cable and for 6 volt systems I prefer 0 better yet 00 Gauge cables for better cranking PLUS a high CCA heavy duty battery. Also a good ground to the frame versus a thin wimpy sheet metal seat box is better. CHECK THE GROUND CABLE AND THE REST OF THE BATTERY AND STARTER AND CABLES AND AT THE BATTERY

John T

JD Wiring

(quoted from post at 20:07:48 03/20/12) hello all, i am new here. i am 28 and just bought my first old tractor to restore a 50 john deere late model b . problem is when i shut the tractor off, the ammeter shows i am drawing current. some one in the past took the wires off the voltage regulator. the regulator is a 3 terminal. can anyone tell me what wires are supposed to be connected where, or if this regulator will work. it has a field, generator, and battery terminal. i have read a couple places you need a special light switch for it to work. mine just has a plain toggle switch. they had the field wire on the generator grounded. also the starter turns over very slow, too slow to start the tractor even with a brand new, fully charged battery. (i disconnected the generator to keep if from draining the battery) what might be wrong with the starter. thank you very much for the help........... carl

Click to expand...

And after doing everything John T said, if the starter still rolls the motor over slow, it probably needs to be rebuilt.

Ya know some of those 6 volt starters dont exactly set the world on fire when it comes to cranking speed anyway EVEN IF ALL IS IN GOOD SHAPE

Big heavy high CCA battery,,,,,,,00 Gauge Cables,,,,,,,,EXCELLENT cable and battery and especially frame ground connections,,,,,,,,,are allllllll a must and then as you note starter OR START SWITCHES ALSO may need attention..

Fun chat, hope were helping

John T

hi guys, thanks for the help. apparently the starter is turning over just fine. started the tractor today with no problems. i am just used to 12v systems. this tractor is the first time i have seen a 6v system in action. about the generator. i will hook it up like you guys said. as of now i unhooked the generator to keep it from discharging the battery. i get the tractor back to my house tommorow so i will hook it back up and see what happens. thank you........... carl

hello. the regulator on my late model b has 3 terminals evenly spaced apart. there is a resistor wired underneath it. my guess is to replace the light switch with the resistor built in it. inside the box are only two relays or cutout units. another question, to what terminal would i hook up the wire going to the light switch. it is in the same wiring harness as the wire for the ammeter. thanks again for your help