6 volt vs. 12 volt

Thanks

Check the ground. On my 70D (6 volt), the starter turned slow at first after engine overhaul, but good on 12 volts. Cleaned ground cable on both ends, and it turned over like new.

The actual voltage to the pony coils after the switch mounted resistor is around 4 v, so it would take an appropriate resistor to drop to that voltage. On top of that, to be correct, the voltage should bypass from the starter switch during cranking so that the coils see full battery voltage while the starter is dragging the voltage down, until the foot switch is released.

Then if you used a dropping resistor to get from 12 volts to 4v, those wire wound resistors can change their resistance a great deal as they get warm and then hot.

You'll run a big chance of burning out coils if you try to run it on 12 volts, unless you can get a dependable regulated voltage like through a solid state voltage regulator (like a LM309K in a TO3 case). That way you could feed it's fixed output of 5v to the distributor all the time. That might work.

Then you have to bump the generator to put out 13-14v or so. If you don't have an auxilliary equipment power requirement calling for 12 volts, I think you'll have an easier time getting the pony starter to work than to work with a 12 volt system.

Frank-in-Tallahassee
70D // 855

Those resistors get pretty hot even when they're working correctly.

Another thing on your starter would be to maybe pull the armature out and have the commutator turned if it's groovy, and then cut out the insulation in the slots. You can really pick up efficiency on those 6 volters if you really make tight clean connections, and that goes for the brushes on the armature. 6V just doesn't tolerate dirt, paint, and greasy moisture.

Later !

Frank