1950 B ignition wiring

Jeffm

New User
I recently inherited a 1950 "B". The igniton switch has no wires connected. It is a key switch with 2 posts on the back. Can anyone tell me where to connect the 2 wires.
 
If its a battery powered coil ignition heres a wiring diagram. Its for a late B that used a Wico XB (looks like an X Magneto) battery powered distributor. If your tractor was converted to a Delco distributor, the ignition output would simply wire instead to the coil (its input NOT to distributor terminal). If you have a Wico X Magneto (Do NOT put voltage on its terminal) a switch can be used to ground the mags side kill terminal post but thats a totally different wiring then posted here. Be sure you have a Distributor (Wico XB or Delco) and NOT a Mag before you wire it as this diagram shows.

John T
B-3-Jpeg.jpg

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Are you sure you have a distributor and not a magneto? If you have a magneto, it does not require any connection to the battery as it will generate its own power for the spark. The mag would have a plate that says something like WICO XH-1042

If you do have a distributor, one side of the switch would be connected to the hot side of the battery and the other side to the coil. If you have a distributor with an internal coil such as the WICO XB the wire will attach to a post on the side of the distributor. It is critical NOT to attach power to a mag.

Kurt
 
It kind of looks like (give us a close up of the coil/distributor/mag) theres a can coil there close to the "distributor"

If so the BAT Input terminal of an Ignition Switch woudl receive hot battery voltage from the load (NOT battery/starter) side of the ammeter and the IGN Output side of the switch wires to the small coil terminal thats NOT the terminal that wires to the side of the distributor. If its Delco with that external can coil its kind of like the diagram I posted except the IGN out of the switch wires to the coil (small input terminal NOT output to distributor) instead the side of a Wico XB distributor.

It was originally Positive ground meaning the IGN switch wires to the coils - while the coils + wires to the Delco Distributor (unless you changed it to Pos ground in which case swap that and the ammeter leads also get swapped and be sure to Polarize the genny before you start it)

If its a Wico C or X Mag do like Kurt and I told you

PS the pic also looks sort of like a Wico C mag so I cant say what you have absent a good close pic

John T
 
I tried to lighten his pic and it looks like theres a can coil?? and the other "thingy" looks like a delco distributor ??? If I didnt see the coil the "distributor" almost looks like a C Mag?? Maybe he has an XB with an external coil?? Darn if we know

John T
 
I sure appreciate the time you are spending on my question. I can get a good close up pic this weekend. I can tell what I know for sure right now. It is positive ground. The "can coil" as you refer to it is about the size of a 12 oz can of coke.The coil has one wire on it going to the distibutor- the other post on the coil does not have any wires on it now but does have the remains of a quick connect type wire connector on it.Your comment about connecting to the ammeter makes it sound like you are on the right track as the local JD dealer said one ignition wire should go to the ammeter and the other to ground. If this is the case would I still need to polarize the generator? Thanks again.
 
Does seem odd that this one coil wire would be missing from what otherwise looks like a very nice 'n well maintained tractor. The detail photo will tell.

Kurt
 
That comment about one wire to ammeter and other to ground IS WRONG AS RAIN. The ammeter has hot battery voltage so do NOTTTTTTTT connect either terminal of it to ground.

1) The Load (NOT battery/starter) side of ammeter supplies hot battery voltage to the BAT input terminal on an Ignition switch. If it had a 4 termnal VR with an L terminal, the VR"s L would feed the voltage to the switches input instead of the ammeter

2) The Ignition switches other (hot when ON) terminal wires down to the input (NOT to distributor) small coil terminal

3) The coils other (NOT from IGN switch) terminal wires to the lil side terminal on a Delco distributor.

If you had a Wico XB distributor, then the Ignition switches IGN output wires to the side input terminal on the Wico XB distributor

Its like the diagram I posted EXCEPT the ignition switches IGN output wires to the coil instead of to any Wico XB distributor.

Dont make this any harder, if its a Delco distributor its almost like the diagram, just wire the IGN switches output (HOT when ON) to the coils lil - terminal and its lil + wires to the Delco SIMPLE AS THAT

Id polarize the genny before start up just to be safe

John T
 
I just have to jump in here. As nice as that tractor looks , you must have either just finished at least a cosmetic resto or bought it that way. Either way , someone has had to have started it up somewhere in the process. Have you ever heard it start up? Give us some history. I would almost guess it has had a mag put on it. ( they came both ways) Why would anyone get a tractor looking that good without hearing it start and run first?? There's got to be more to this story.
 
I have seen it start and run many times. My father finished a full restoration on it about 3 years ago. He also did full restores on 4 other JDs. A 1941 H,a 1954 50, 1955 70 Diesel and a 1956 420. All are beautiful and I drive the 50 and the 420 every weekend. So, I have no idea why he would have pulled the key switch ignition off the B.As I stated in a previous post I will get a good close up pic of the " ditributor / mag / coil" and post it.
 

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