Case 300 Gernerator

I have a Case 300 Utility Diesel. The 12 Volt generator appears to be not working. How do i test the generator. Also is there wire diagrams available for the tractor.

Thanks Mark

need to know A circuit or B circuit.


try this.

look at vreg. flip it over. if theire is a bias resistor between the field tab and ground.. it is A circuit.

If you see 1 or 2 resistors, and one is from armature to field, then it is B circuit.

For A circuit, remove belt and wires from genny.

jump bat hot to armature.

jump field to ground... genny should spin ( motor ). if it does spin.. it USUALLY will charge.

If it spins, hook back up and re belt.

start tractor.. use volt meter on battery.. if at mid high throttle you do not see about 13.8-14.4v then jump field to ground at the genny... if still no charge, then jump arm and bat at the regulator. if charge comes up suddenly, then reg is bad.


For B circuit, remove belt and wires from genny.

jump bat hot to armature and field... genny should spin ( motor ). if it does spin.. it USUALLY will charge.

If it spins, hook back up and re belt.

start tractor.. use volt meter on battery.. if at mid high throttle you do not see about 13.8-14.4v then jump field to armature at the genny... if still no charge, then jump arm and bat at the regulator. if charge comes up suddenly, then reg is bad.

Thank You, It is a "B" circuit I'll test the gen tonight. If it is bad, do you know were i can get a rebuilt from?

Thanks Mark

Sorry can't help you on where except to say to try a mom n pop shop or places like here or Napa, Napa can get ford gennies of a certain age.

Good luck
On the test