Farmall H Electrical Question

Sat Nov 09, 2013 2:28 pm

The PO must of had some issues with the generator keeping the 6v battery charged. So, he left the belt on the generator pulley, but disconnected all the wires to/from it. Put in a 12v battery and did some rewiring. The tractor starts, but it still has the positive ground off the battery.

Here's the question: I started the tractor with the battery in place, but once I disconnected either cable from the battery, the engine died. How's that? Would this mean that the magneto is also disabled and the tractor is getting its "juice" directly from the battery during operation? Can't you take the cables off a Cub 6V system and the engine continues to run?

I'm planning to address the electrical next, restoring it back to original 6v system. But this situation was new to me.

Re: Farmall H Electrical Question

Sat Nov 09, 2013 2:53 pm

That would normally indicate that the magneto has been been semi converted to a battery ignition system. The magneto coil disconnected or removed and an external coil added. Both the magneto and battery powered ignition systems have to have a functioning coil.

Check under the hood and around the engine for a standard coil. Actually just follow the ignition wire from the center of the magneto's distributor cap to it's termination. If it winds up back in the magneto - then I don't have a clue.

Multimeter - check for battery voltage at terminal on side of magneto.

Re: Farmall H Electrical Question

Tue Nov 12, 2013 10:44 am

I have to correct myself: My H is a battery ignition system, not a magneto (see below).

Image

From what I've been researching on the web, the battery ignition systems were not introduced until the early 1950's, hence, my 1945 would probably have had a magneto.

Would this explain the generator being disconnected from the electrical system? Or why the tractor engine dies if either battery cable is disconnected?

Bottom line question: In a battery ignition system, does the battery have to be connected to the electrical system in order for the engine to run AFTER it has been started?

Re: Farmall H Electrical Question

Tue Nov 12, 2013 12:37 pm

Stanton wrote:
Bottom line question: In a battery ignition system, does the battery have to be connected to the electrical system in order for the engine to run AFTER it has been started?

Yes, it does, Stanton. The battery system gets it power from the battery, unlike the mag system.

Re: Farmall H Electrical Question

Tue Nov 12, 2013 12:53 pm

Stanton wrote:Would this explain the generator being disconnected from the electrical system?
There is a fault or faults in the generator, cutout/regulator, or the wiring. That is why the generator/regulator was disconnected and the belt removed.

I realize you want to return the tractor to original condition. Investigate the cost of repairing the original 6 volt system and the cost for converting to 12 volt single wire alternator electrical system.

Re: Farmall H Electrical Question

Tue Nov 12, 2013 1:03 pm

Thanks for the responses.

I have a good alternator that I could go the 12v route, but am leaning toward the 6v original. I'll let ya'll know in the days ahead.

Thanks again.

Re: Farmall H Electrical Question

Wed Nov 13, 2013 11:20 am

IH sold a kit to convert the earlier magneto ignition tractors to battery ignition. Many magneto tractors were converted to battery ignition.

A well-maintained magneto works just fine, as does a well-maintained generator system.

The problem is/was MAINTENANCE. People didn't maintain them, and had no idea what to do when they stopped working. It wasn't that they were terribly complicated or hard to fix. People just didn't understand how they worked.

Battery ignitions and alternators for some reason don't require near as much maintenance.

If we had had the Internet in the 1940's, we'd probably still be running magnetos and generators.