Couple things, You may have a bad battery, solenoid, starter or locked engine. You indicated 127mv at the starter lead of the solenoid when the key is turned. This should be 12v as the solenoid passes the 12 from the battery connection to the starter. If the solenoid is clicking and the starter is not turning, then I would think bad solenoid. You can test in one of two ways: Use car jumper cables and put one of the red leads to the starter large red connection and touch the other end to the battery Pos+ terminal. If the starter spins, bad solenoid. Second way, using a larger screw driver jump the two large red connections of the solenoid together, same thing with the starter spinning. This is not the preferred way and is usually done if you stuck in the field and don't \have a jumper wire.
If the starter does not spin, but just clicks, it mat be locked against the flywheel or bad itself. Before testing, make sure you can rotate the engine by hand 360 degrees. Will be tight. If it doesn't turn remove the engine cover, get rid of any critters or grass and see if the starter gear is meshed with the flywheel. If it's ok, then remove the spark plug and see if you can rotate the engine.
If the starter does not spin, but just clicks, it mat be locked against the flywheel or bad itself. Before testing, make sure you can rotate the engine by hand 360 degrees. Will be tight. If it doesn't turn remove the engine cover, get rid of any critters or grass and see if the starter gear is meshed with the flywheel. If it's ok, then remove the spark plug and see if you can rotate the engine.