What are you attempting to wire to your Ignition switch? Driving Lights, or something else?
Your Predator 420 engine is probably wired just like a Honda GX390, here's a link to a wiring diagram you could check out:
http://www.engineman.co.uk/ekmps/shops/engineman/resources/Design/elecrtic-start-wiring-diagram.bmp
Your Ignition switch is different from one used in a car or truck.
(its the same type of switch that older outboard boats and motorcycles used)
Your switch has completely 2 separate sections, to activate power(+) and ground(-) circuits...
Your Ignition switch gets it's Ground-source from where its installed to a grounded metal panel.
In the Off-position, your Ignition switch simply acts as a kill-switch. It sends that Ground-signal to the Ignition coil to kill spark and shut the engine off.
In the On/run position, your Ignition switch does nothing;
it simply stops sending that ground signal to kill spark.
(your engine would keep running even if you completely unplugged the Ignition switch...)
The other 2 wires on your ignition switch are a Positive voltage circuit, and they're only function is to activate the starter solenoid when you turn the key to the far right (start/crank) position.
PS:
Use your multimeter to check for any possible function of those 2 little blobs of solder (without any wires connected) on the back of your Ignition switch. You might just discover those 2 are a completely separate, unused circuit of your switch. (also check if they're
always isolated from your other 3-wired switch connections) Because If you discover they
only have continuity with each other in the on position, you could probably solder wires onto them to turn lights (or whatever) on and off with the key...
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