If the starter motor won't spin by stepping down on the clutch or even after it has been bypassed, I'd suspect the starter or other issue. Connect a test light onto the starter motor & test for 12 volts when the ignition switch is turned to the Start position. If you're getting 12 volts at the starter, it's the starter. If you don't see 12 volts at the starter when the switch is in the Start position, then it could be something to do with the ignition switch... sometimes the pin inside the switch breaks which needs replacing. I had a link for how to repair that issue but it looks like it was lost when my computer crashed several months ago. Perhaps someone else can provide that link here if you're not getting 12v at the starter.