My 1939 Ford/Fergusion (9/N 0 tractor) is wired correctly but still burns up the coil after a few hours. The balast resistor is supose to eliminate this but somethings still wrong.........any ideas

 

Sounds like the resistor is still in the circuit when the key is in the "run" position. easy to check with a meter... my guess...

 

Has it been converted to 12V? If so is the coil 12V or 6V?

The ballast resistor is SUPPOSED to be in the circuit in the RUN position. The ballast resistor is bypassed and the coil is fed direct battery voltage from the starter solenoid during START.

The ballast resistor should be 1.3 Ohms in a 12 V system. I am not sure what they used in a 6V system. It has been way to many moons since I worked on one.

 

6 volt systems did not use a ballast resistor. And as stated above the ballast resistor is in series with the coil.
You can buy a coil that is made to run at 12 volts without a ballast resistor.

 

Thanks I think I got a solution to it now. The thing is evidently bypassin the resistor.

 

also try www.yesterdaystractors.com the ford tractor forum there is great

 

Man, did I ever get THAT one backwards... sorry...

 

If it's been converted to 12 volts make sure that it is indeed wired correctly. It may be that it's still setup for positive ground.