If you take a screwdriver to the main leads on the solenoid and touch them together (to make the starter spin) it would answer some questions.
If it turns over, you have a bad solenoid OR starter switch OR bad cable/connection from the switch to the solenoid.
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(FYI, a continuity tester can test your starter switch. If you have a solenoid like mine that doesn't disconnect the smaller pair of wires that go to it, carefully jab the wires with the tester's leads and see if you have continuity when you press the start button, but no continuity when you don't press it. If you get nothing when you press it, the start switch and/or cabling is bad).
If it doesn't turn over with the screwdriver test, you have a bad starter OR connection somewhere between the solenoid and starter.
(Jumper cables from the + on the battery to the solenoid connection to the starter (bolted connections) also server as a better "screwdriver").
It wouldn't surprise me to see a bad solenoid since you cranked it for so long that day. You need to work on your carb adjustments after cleaning it thouroughly. Replace your fuel filter and flush your tank. This should help most of your problems, if not all.