CSER, It's not uncommon for the contacts inside the solenoid to become welded together. For now, leave the small ring w/black wire off and the plug. Connect ONLY the red battery cable to the copper colored terminal (the one without the nut in your pics. Touch negative battery cable to battery. If engine tries to crank, bad solenoid. You may (??) be able to take the solenoid apart and repair the contacts, but best to replace the solenoid.
If engine doesn't crank when touching neg battery terminal, connect small black ring on same post as red battery cable. Touch neg battery terminal. If engine doesn't crank, connect plug. Let us know what happens.
One point I'm VERY confused on is what appears to be a piece of metal (with solder on 1 end(?) going between the 2 large studs on solenoid. Anyone have thoughts??? Bob