Ok, here's where I'm at. I disconnected the pedal and pushed the starter button and it spun freely. I disconnected all the cables, including the battery lead and ground and cleaned all the connections. It will kick-in and spin a few times, then slows after a second to a whine:
https://photos.app.goo.gl/ArIWXwdjAuRlQci52The battery is brand new and motors turns pretty easy by hand. It was already running and actually starts pretty quick normally. I did get a couple rotations out of the starter yesterday and it started and took it for a run, without issue.
Time to yank the starter and have a look?