Not a difficult job butt a regular pain in one to do.
First you will need a circuit diagram with the ignition switch connections on it.
Next pull the plug off the rear of the ignition switch and jump the terminals with some short lengths of wire with insulated spades on each end.
Use different coloured wires so you don't mix them up.
When ever you work on the wiring it is prudent to remove the blower housing and pull the magneto wire (s) off because if you make a mistake and just brush over a kill wire with battery voltage you will be back at the parts store spending way too much beer money.
So now you have the ignition switch jumped from B to S + whatever else is connected during starting.
From here it is out with the test light and follow the power trail all the way to the trigger terminal on the solenoid.
If it is a 4 pole solenoid with both a + & - trigger wire then the - can also be switched.
SO if you get + 12V but no ground you then have to go back, hook the test light to the battery + and follow the ground path as well.
I ground down the probe on one of my test lamps so I can poke it in the back of the plugs which makes things a lot easier .
Usually the PTO & parking brake switch will handle the + 12V and the lap bars switches will handle the ground side.
Then to be really confusing they seem to like to shove a relay or two in just for the heck of it.
