They are not in idle position, but off position (in game) - use throttle or keybinding to put them to idle position. That is done with HOTAS
Warthog by raising the throttle physically (irl) or if they are always physically in idle position (irl) use keybindings to move them from off to idle position (in-game). I personally always use them in idle position (irl) because I don't want to physically raise them. Then I just use the keybindings to put them to idle at start. I currently have
ENG OPER L & R - as engine starters - then at 25% RPM I switch FLOW L & R (moving throttles in game from off to idle) to up to start the engines .