Ballast resistor

[ford 2000]

Tractor appears to have been converted to 12volt. There is a ballast resistor installed, is this suppose to be there? What is the correct installation for it???

 

[awhtx]

If this tractor is the 1968 3 cylinder 2000 from your prior post it left the factory with a 12V, Negative Ground electrical system.

 

[Jerry/MT]

Some one tried to use a 6V coil on a 12 V system so you need a total reistance ( coil + wire + reisitor of ~3.2 ohms to limit the primary current to 4 amps max. You can replace thisresistor and coil with NAPA 12V coil IC-14SB for ~$15. the correct resistance is built in for a 12V system.

 

[ford 2000]

This is the same tractor. So do I need the resistor?? Looks like a patch job. It was wire nutted in.

 

[Rick from NC]

It is my understanding from reading the posts of the gurus on the board that most 3-cyl gas Fords came from the factory with an external resistor or ballast wire. This is because even though the tractors were 12V negative ground the coil remained basically a 6V coil. This was apparently a common practice among many manufacturers for years after 6V systems became uncommon.

So yes you need the ballast resistor with your coil unless you change to a true 12V coil as mentioned in a previous post.

I'm still learning (probably always will be) so someone may jump in and correct me if I flubbed up.

 

[awhtx]

The factory wiring harness had a high resistance wire between the key switch and the coil that served the same purpose as the ceramic resistor. That wire probably melted so someone replaced it with standard wire and the ceramic resistor. The easiest fix is to get rid of the resistor and get a new 12V coil that is marked "No External Resistor Needed"- that is the NAPA IC-14SB that Jerry/MT mentioned. You can connect your wire from the key switch directly to it.