Wiring on B Farmall

mr.dwreed.ast · Apr 11, 2019

I have a '46 B that I'm restoring. I need help with making he wiring harness. Should be simple, but every website diagram I've found is for converting from 6 to 12 volt and adding an alternator. The tractor was converted to 12 volt sometime in its life. It has a 12 volt battery and starter. When I picked it up from the farm, the wiring was shot.

I understand the benefits of an alternator to recharge the battery. At this time, I'm just wanting to get her running. I may add an alternator at a later date, but the projected life of parade runs and joy rides allows for use with out one.

Does anyone have a diagram for wiring this tractor or suggestions of where to find one?

Thanks.

jCarroll · Apr 11, 2019

I have the wiring diagrams in my Farmall A,B manual. It;s so simple I could tell you which wire goes to which terminal, but................
if you don't have the "original" switch, generator, etc I'm not sure that would be much help.

I don't know how to take and post pictures - which is really what you want - sorry.

tractorsam · Apr 11, 2019

Well, if you?re not putting an alternator on we?ll
assume you?re not running lights either. After that it
depends on if you have a magneto or a distributor. If
a magneto you need a way to ground it to shut the
engine off. If a distributor then all you need is a
ground strap on the bat neg post, a hot wire from
bat pos to the starter, a wire from the starter post to
an ignition switch and then a wire from the switch to
the coil + terminal and one from the coil - to the
distributor. Sam

fixerupper · Apr 11, 2019

The genny didnt work on our 6 volt B for a couple years back when dad was mowing with it nearly every summer day. It had a mag and started first or second time over so we didnt need to throw a charger on it more than once a month. 6 volts spins a B very well but I can understand the convenience of an alternator too.

Dave H (MI) · Apr 11, 2019

Why didn't you ask this on the IH board? There are guys there who may not hang here. Just saying...it's a good plan. You can buy a harness for that tractor that will come with a diagram also. Everything enclosed in loom...looks nice, works great...

mr.dwreed.ast · Apr 11, 2019

No, no lights.

The tractor has a magento.

Have a push starter button, kill switch and ammeter. Have a pretty good idea of wiring path, just looking for confirmation before I burn something up.

Thanks,

mr.dwreed.ast · Apr 11, 2019

Sorry, first time poster.

Crazy Horse · Apr 11, 2019

This link below covers all of those magneto ignition Farmalls from that era. This is the factory set up, not sure if you have the original
generator with the single-tower cutout switch mounted on top of the generator, or even the factory light/charge control switch on the dash.
Anyways, here it is .....
Farmall magneto wiring diagram ....

rvirgil_KS · Apr 11, 2019

do an internet search for Bob M Farmall diagrams

mr.dwreed.ast · Apr 11, 2019

Thanks Crazy Horse- This helps.

Right now, this is what I should be looking at:

12 volt battery--positive ground.

From battery (-) to starter post, to push button switch, to ammeter, to ???(no generator or lights--tractor has had neither in my life time--45 years)

Separate wire from ground to kill (run/stop) switch to magneto post.

1946 BN IHC · Apr 11, 2019

I finished rewiring our BN( same wiring pattern) over a year ago as I finished rebuilding the tractor. I think I still have my diagram I use to design the harness.
I used 10 gage instead of 14 gage wire on all runs from and to generator and coil, 14 to the lights. Added a special run for flair flashers since I am sometimes on the road, for safety. Further to this I utilized the services of a starter coil so no one can accidentally start the tractor without the key, since I live on a camp ground that has a lot of people at differing times during the year.
If you would like to write me, my email is open and I will share what I have with you. I could send it by post to you, the diagram.
Wm.

old · Apr 11, 2019

Which way you ground it when you do not have a charging system does not matter. But in the future if you put on an alternator ground will matter and it will matter so much that if you hook it up wrong you will let the smoke out of the alternator the moment you hook up the battery. So if it was me I would hook it up - ground

mr.dwreed.ast · Apr 11, 2019

Thanks.

jeffcat · Apr 11, 2019

I double that OLD. As soon as you see something was converted and then go positive, and then add an altinator at a latter date my skin started to crawl! This is when somebody is getting into the hobby and needs a good guide to show them now and then. Amazing how much smoke is in tractor wiring. My dad found out a six volt battery can turn a 3/8 7/16 wrench very bright orange!!!

Wiring on B Farmall

mr.dwreed.ast

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jCarroll

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tractorsam

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fixerupper

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Dave H (MI)

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mr.dwreed.ast

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mr.dwreed.ast

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Crazy Horse

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rvirgil_KS

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mr.dwreed.ast

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1946 BN IHC

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old

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