John Deere A ignition

[LWG]

Hi guys. I'm to get a 1948 John Deere A, that has been setting for fifteen +years, running to sell. It had a dead 8 volt battery in it and the generator says 12 volt. An 8 volt battery is expensive and harder to find than a 6 or 12. What would you do, put it back to the 6v, put in a new 8v, or upgrade to the 12? Thanks!

 

[Fixingfarmer]

12v cheap car battery will be fine

There’s a ton of room under the seat mine has a big tractor battery I woke up from a dead pair off the 8220. Anything with top post and around 500 cca and above which describes most decent car battery choices.

 

[a49deere]

Should have been 12v, positive ground originally. they used two-6v batteries in series to get the 12v for starter and lights. a 12v battery will work, make sure to hook positive to tractor frame.

 

[matthies]

Does it have a mag or distributor? The reason I ask is that since it had an 8V battery would need a resistor for the points if putting a 12V battery in. Wouldn't think an 8 volt would even spin the engine.

 

[LWG]

Does it have a mag or distributor? The reason I ask is that since it had an 8V battery would need a resistor for the points if putting a 12V battery in. Wouldn't think an 8 volt would even spin the engine.

It'a a distributor. I'm concerned that if I put a 12v battery in, I may cook the coil or something else that was set up for a lower voltage.

 

[matthies]

Get an ignition resistor and wire it in after the switch on the wire going to the coil. You will appreciate the 12 volts when starting.

 

[Fixingfarmer]

Usually an 8 volt conversion on a ford used the original stuff and a 6 volt coil and it’s completely unnecessary even on that. I’m baffled why someone would do it to an A. It’s highly likely someone thought it was 6v like a B and tried the 8v it may not have even started for them.

You should check if the vr is charging the battery when you have the 12 in and I think there was a way to adjust them. Or purchase the VR. Coil should be resistor free for 12v originally I think Matthies unless someone swapped it and that is an assumption ohm across wire with multimeter from switch to other ground side of coil you should have 1.5 for 12v I would include the wire to make sure you don’t have a resistor tucked inside although you should be able to see it.

It’s highly likely this is original