You are right. Had a heck of a time, though finally got around the problem.
Initially starter wound up, but got message "N1 is above 15% no light will take place; after which starter wound back down.
Thereafter: dead; dead.
Tried all manner of things: uninstalled; reinstalled; flew different plane and came back. All to no avail.
Here's how finally got it to start and fly:
Uninstalled it.
Deleted C>Users>{user name}>AppData>roaming>flightgear.org>aircraft -data>org.flightgear.fgaddon.stable_2018.extra..
(apparently this leftover file prevented restart)
Reinstalled.
clicked Fly
Unfortunately, had to repeat above procedure for every flight.
Made sure throttle was closed.
Clicked autostart.
Waited until engine spooled up before adjusting throttle.
Thereafter everything worked fine.
Kind Regards