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Classic/Antique Car Repair/1931 model A fuse between coil and generator gets hot and blows


I recently purchased a 1931 Model A Coupe. In taking the radiator out I touched the wires from the relay that my horn plugs into and blew the fuse between my coil and generator. I replaced the fuse and found out the relay or whatever it is on top of the generator had burnt the copper coil wire off so I reconnected it and it started. This morning the battery was dead and when recharging it I noticed that little fuse was extremely hot and the charger was pegged out. I pulled the fuse and the charger dropped to 3/4 charge.

Sounds like you have a damaged or stuck cutout. The cutout is what is on top of the gen.  My advice is to lose the gen and the cutout.  And put on an alternator. Much better in the long run.  We all run alternators. Your batt went dead because your cutout stuck and tried to run as a motor all night.  
If you want to keep the gen. Then take the cover off of the cutout so you can see it operate. I dont think you have a fuse between the coil and gen. The fuse should be between the hot wire on top of the starter, from the battery and the main circuit. Have to go, more later. Jack

Back now.  The gen, when spinning fast, above idle, puts out enough current to pull the contact down and connect the output of the gen to the electrical system.  Since it puts out more than 6 volts, it charges the batt.  If the contact sticks closed, the current flows from your system to the gen and it becomes a motor and tries to run.

Make sure you are wired correctly.  I hope the new cutout fixes it.  Let me know if you still have a problem.  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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