As mentioned before, the cooling fan of my engine needed some attention:
As a result of this, the crankshaft could move a little along its axis. Apparently the engine turned a bit in this state, cause I can see some damage to the backplate:
I re-tightened the fan and locking nut, but used red loctite this time (previously I used blue loctite here). Hopefully this will keep it glued a bit longer.
After realigning the governor-sensor, the result looks like this:
