John Deere 50 coil wiring

I need a little help. I have a 1953 JD 50 with the Delco dist. and external coil. Which side (+ or -) does the distributor wire go, and the other goes towards the key switch?

Also, do I need a resister in the system somewhere? Thanks!
 
If the tractor is still (+) ground at the battery, the (+) terminal of the coil goes to the distributor.

IIRC, originally the ignition ballast resistor was at the ignition switch. Whether there's still one there, or if you are using a coil that needs a resistor, or a "true" 12 Volt that doesn't, I can't see from where I am sitting!
 
Bob has you covered on Polarity. Unfortunately the JD SM 2029 Wiring Diagram lumps the 50 as well as 520 series together but I'm not sure that's correct for your tractor??? NO WARRANTY NOT BEING THERE TO SEE WHAT YOU HAVE

The 20 series (as correctly shown in diagram) did have the external series voltage dropping (12 down to 6) ballast resistor mounted near the steering column or down by the coil and used a 6 volt coil. HOWEVER some (maybe all??) the early numbered series like 50 and 60 and 70 etc may NOT have used the ballast and instead a full 12 volt coil. ALSO I have seen so many mods over the years I just cant say what you have regardless how it came original

If you have a full 12 volt coil (NO ballast required) you would NOT use any external series voltage dropping (12 to 6) ballast resistor, but if you have a 6 volt coil (like the 20 series used) you obviously do need one or the coil will overheat and the points burn up soon.

I just dont know sitting here if your tractor has a 6 or 12 volt coil, but it only needs a ballast if its a 6 volt.

Best I can do

John T
50-1-JPEG.jpg
 
Thanks all for the quick reply. I do have a 12 coil, so no resistor. That is good. Thanks for the info, I will verify I have it correct. Thanks again!
 
The 50 deere I worked on a couple years ago was wired like the diagram shows. Note, it has bypass of resistor coming from starter switch for full battery voltage to coil during cranking. Also, has a grounding wire from distributor side of coil to ignition switch. That prevents starting with ign switch in the off position by grounding that bypass circuit. I think that is a good feature (both, the resistor and ground wire) and would keep it incorporated in the system.
 
Thanks for the additional reply. My tractor does have the 12 volt coil and no resistor. I changed the coil wires around (you know it ran ok with the wires connected backwards-go figure), but at least now it is correct. Thanks all! I think I am all set.
 

Not trying to hijack this thread, but is it possible to use a 12 volt coil with the bypass resistor? My 50 has always had a 12 volt coil as long as I've owned it. It also has the resistor, but I don't know if it's hooked up or not. I've never looked at it that closely. I just know it's there.
 
(quoted from post at 09:38:23 08/26/15)
Not trying to hijack this thread, but is it possible to use a 12 volt coil with the bypass resistor? My 50 has always had a 12 volt coil as long as I've owned it. It also has the resistor, but I don't know if it's hooked up or not. I've never looked at it that closely. I just know it's there.
t really depends on your definition of "12v coil".. There are those intended to be used with a resistor (they are lower primary resistance coils) and there are those intended to be used without a resistor (higher primary resistance). Some are marked "use with" or "use without'' external resistor. Some are not.
 
The one I took off of it said "12 volt with internal resistor". The one I replaced it with said "use without external resistor". I assume that meant the same thing?
 
(quoted from post at 14:02:16 08/26/15) The one I took off of it said "12 volt with internal resistor". The one I replaced it with said "use without external resistor". I assume that meant the same thing?
ound equavilent
 

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