Prolly is it not wired correctly.
If the plug was cut off, I'm hoping the switch at least has screw terminals??
To run, it needs power to the + side of the coil when in start and run position.
Also needs power to the solenoid in start position.
In the stop position, no power is applied to the coil or solenoid.
That should get it running.
Just use your meter to determine those positions on the switch.
Most "will fit" switches have terminals marked with:
Battery,
Run,
Start,
and Stop,
If they are made for a magneto ignition. ( that terminal is grounded in the stop position)
Your going to have to determine what components the wires lead too, by following them and using your meter, checking for continuity.
