Most starters have 2 wires, 1 large and 1 small. The large carries the main voltage from the batt to the starter windings. The small one is what energizes the starter, it is fed from the start switch thru all the safety switches. You can run a wire from the batt and just touch the small terminal, starter should engage. If not, ck for batt volts at the starter on the large wire. Loosen the jnut and clean the terminals. If the starter now engauges, safety switches or ignition switch.