I decided to fix the engine as it was warming up, changed the parts, assembled it, inserted the key and started it, the starter turns and the battery drains. The gear matches, the fluids changed. MSC EDITOR shows that all bolts are tightened
THEmenpro A classic, this has happened to me sometimes and I had to tow it to the service on a tractor, although every time I assembled the engine the same way (sometimes even the piston flew out of the blue).