Brown wire on starter relay. This is the 12v trigger input for that soleniod few inches off the soleniod there will be a bullet style connection. Unplug and touch the wire to the battery lead connection at the relay. Easy way to eliminate key switch. If it clicks and does not operate starter, then take the starter wire off of the relay and touch the wire manually to the battery lead.
I believe the starters have solenoids built onto them.
I have used and new starters and relays for these on a shelf at the shop. PM me if you need any parts. Pretty sure I've got a brand new starter that was out of the box I would give a special deal on.
Possible problems
Battery leads
Relay
Starter
Key switch