If you turn off the magnetos or pull the mixture all the way out the engine should be ‘running’ in the sense it is generating any power, but if it is windmilling the whole thing is still turning. So it will make some noise, but less noise.
If you turn off the magnetos or pull the mixture all the way out the engine should be ‘running’ in the sense it is generating any power, but if it is windmilling the whole thing is still turning. So it will make some noise, but less noise.