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Classic/Antique Car Repair/Battery drain - generator shorting


Hi:- Have a 1930 Model A Ford.  If it sits for a couple of days the battery drains.  New wiring harness was installed.  If I disconnect the battery and remove the input wires from the cutout and check with an ohm meter I get basically 0 ohms between the input and output of the cutout however if I remove the cutout entirely it shows no continuity between the input and output of the cutout.  I assume this means the points are open and the cutout is okay however with the cutout removed and the generator on the bench I am getting 0 ohms between the casing of the generator and the top terminal post on the generator.  Does this indicate the generator is shorted and needs a rebuild.  Thanks in advance ---   Joe

I think the gen is ok.  My first guess is a battery problem. When they get three yrs old, things can happen inside. Make sure you have a good batt.  Charge it and let it sit for a few days, assuming you can do without your A for that long.  My guess is that it will drain down.
If the batt is good, then the cut out is sticking closed.  Those cut outs will not stick every time.  You can tap them and the points will open,  drive it a while and it will decide to stick.
Now, here is what you should do.  Put on a 6 volt alternator and leave the gen and cut out on the bench.  No more cut out, and no more run down battery. Almost all of our members are running the alternator. Cut out  and regulator is built in.  
Good luck and have fun. Let me know what you find. Jack

Joe, I reread your note.  Take the generator apart and find the short. The output and case should not be touching.  Look hard at the brush holders and wires. Your problem is in there. Good luck again, and sorry I missed it. Jack

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jack bahm


Only repair type questions on the 1928-1931 Ford Model A.


Owned one when I was 15 yrs old, and now have owned 5. Still own and play with 2 of them.

Oakleaf region of MARC. Model A Restorers Club. I have put several Model A videos on the Oakleaf site that may be of help. Things like how to start the A, how to Time it, how to troubleshoot it.. Go to and you will find them. Also, go to and search for "jackbahm" and you will find over a hundred videos. Many about the Model A and our outings. jack

"More than you need to know about cars." Just a small book for Car Nuts. "Model A Ford Tips and Hints" "Get A Horse" (What to do when Henry's Lady quits on you.) or Snyder's Antique Parts. "Engineering Stuff" (For the Kid who likes to take things apart and get them back together). Kids book for ages 10-16. 2012 Many Model A movies that can be found on

BSME LSU, 1958, Masters of automotive engineering from the Chrysler Institute of engineering, 1960, MBA Mich State, 1976. Worked as an engineer at Chrysler from 1958 to the end of 1991.

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Two patents while working in auto industry. Go to this site for my Model A videos.

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