Ford 641 12v conversion

[WranglerX]

Yes, replace the coil. But there is no resistor to remove. No matter how you deal with the voltage change your fuel gauge/sender combo won't like the polarity change.

Is the 641 a positive ground system (stock).... Just asking....

 

[RickB]

Is the 641 a positive ground system (stock).... Just asking....

It was when it was new.

 

[MoBill]

Yes, it's positive ground.

 

[John0829]

Do not make it positive ground if you convert to 12V.

 

[MoBill]

I think I might try another voltage regulator and see if that solves the problem. It's the simplest and least expensive thing to try.

 

[Smokeydog]

Converting my Ford 850 made it one of the most dependable tractors in the shed. It would always start.
Went to autozone and got one wire 12v alternator that someone turned in that tested good but bought a new one. $15 core. New coil. Had to partially saw off a mounting aluminum lug with a hacksaw, long 3/8”carriage bolt and added a piece of flat bar stock to the adjustment arm. Used a string to measure for a new belt. Can’t remember replacing the headlights but must have. Installed a rubber mounted light for the back. Didn’t have a fuel gauge? Did replace the amp gauge because the glass was broken. It always got a used battery hand me down because it didn’t need much to start. It was the cheapest tractor to keep running for our 45 year relationship. That tractor was made to last multiple generations.

At one time we had 8 volt battery in it to improve starting. Haven’t seen those for many years.