If you choose to start at an airport and don’t specifically select a gate then it starts on the runaway with the engine already running. Does for me at least. If I want to cold start I have to select a gate/ramp. You can assign your copilot (or was it AI pilot?) to handle your checklists as well.
As for the throttle have you gone into the control settings and try reversing axis? Do the engines actually shut off or just go idle?