Starter switch

[rob love]

Ah, I see that now. Perhaps you could gut the chevy switch (or any of the many similar switches used on tractors) and move new contacts into the original switch.

Doesn't have to be a diode for the wire of course. You could go old school and use a relay. But there are diodes small enough that you can almost hide them within the sheathing for the wire.

Personally, I use a 12 volt battery on my starter, and the 6 system merely runs the distributor, a solenoid, gauges and lights. Incredible starting without the load of the starter on the system.