Looks like you have an issue with keybinds, which is constantly sending the signal that engine 1 and 2 is in cutoff. So check you controllers - might be a toggle switch bound to something (like the 2 eng switches on the thrustmaster airbus throttle for example). Quick check in the manual suggests it could be "SET ENGINE 1 FUEL VALVE" but i would also check if you have anything bound related to mixture.

Many thanks for the answer.