MF 65 alternator wiring questions

wilddouglas

New User
Wires snagged while mowing some brush--I noticed this when smoke started pouring out from underneath the dash. I turned it off but not before the insulation had melted away from some wires going to the ammeter and from the coil.

Upon closer inspection, I saw the pulled wires from the alternator, which a previous owner had installed that included a chunk of metal on the wire that always got hot: see photo. I have wiring diagrams in order to replace the burnt wires, but since the alternator is not original, I'm at a bit of a loss as to how to wire the alternator. In the photo, the little metal cylinder that always gets hot is in my left hand. The gray wire in my right hand has clearly pulled out from under a nut. Any guidance on how all of this goes together, what that little metal cylinder does or why the wires to the ammeter and coil melted would be greatly appreciated!

cvphoto133232.jpg
 
That looks to be a Delco 10si so the big wire goes to the charge stud which is the stud the wire from the 2 wire plug goes to. The small wire goes in the other side of the 2 wire plug and should be marked #1 on the alternator
 

I am guessing the little round thing that gets hot is a resistor, installed in the excitation wire of the alternator to prevent feedback which would prevent the engine from shutting off.

The wire with the ring terminal should have battery voltage on it and hooks to the alternator output post. The smaller wire, with the resistor in it, hooks to the loose wire in the two-wire plug in the side of the alternator. That wire excites the alternator when the key is on.
mvphoto95907.jpg
 
Its not perfectly clear in your pic, but it looks like one of the wires goes from the white plastic plug to the large charging stud. If so, then all the rest of the remarks are accurate. You need to freshen up the insulation on the large wire, because that's where your short was that let the smoke out. It's a direct shot back to the hot side of the battery and was probably grounding to the chassis somewhere when it came loose. steve
 

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