Having devised a way to couple the flywheel with a drill I proceeded to rotate the engine for a few minutes as you suggested and I saw some sparks of the pins are released, indicating that the coil produces a current ...... I then reassembled everything and as soon as I'll make a start-up test.
Immediately remove all doubt I would have liked but I had no gasoline available.
So I decided to devote the remaining time to the foot of the engine.
I unscrewed the plastic cap and I started to feel a very strong smell of rotten eggs come from the interior of the foot;
I poured the contents into a bucket e. .. Horror!

It came out smelling water and a few drops of a dense black liquid that resembles crude oil.
Here's the photo.

I proceeded to restore the proper oil level with the W140 and I closed the lid.
If the engine starts I would like to make it run a bit of time in the bin and then change again to be sure the oil of the foot, what do you think I do well?