I did a flight earlier and found something that worked
Put knob in CRANK first for about a minute, then switch to IGN START, and turn on the engine that's running hot. It'll take a while to cool down but eventually started for me
It seems like (at least for me) if you put it in IGN START first, it'll stay hot and never cool down and you'll have to exit the flight
However, after it worked, the sim crashed to desktop about an hour into the flight. So whatever. LOL