I know this is not stock, I edited the xml and in a normal use of the game tools this wouldn't happen.
The problem here is that in engines with high fuel consumption rates if the craft has less fuel than what is used in a game tick it generates the same force no matter the fuel quantity you have
For example, if the engine consumes 1000 units of fuel/electricity every tick a craft with 999 units and a craft with 1 unit generate the same amount of force
@AndrewGarrison it would be possible to check something like if fuelconsumption>fuel apply the % force relative to fuel/fuelconsumption? I don't know the impact of a conditional every tic