Thanks for all the advice and help - the wire problem is solved (
for the moment).
Here some photos and info how to change the wire to
Biltema snowblower model HST 8613.
The snowblower has to be lifted up even if the beast weights 150 kg (300 lbs). It’s pretty easy to lift on three boxes, first the front, then left and then right...
The wire was broken, I marked with the red arrow where the wire was cut. Just at the handle.
Between the belts, under the snowblower are two plates to open. Behind those is the access to the wires.
Above, two plates 1 and 2.

Above, there you see where the wires comes. In this photo you see the left clutch wire coming down in a tube from left. The right one is just above, not seen in this photo.
Above, here a photo from right below looking up. Here you see both clutch wires, left below, and right above.
My next project is to change the wire I’ve circled. I have NO IDEA how to access that wire! Do I have to take a part the whole snowblower? Any hints or advice?
Once again, thanks for all the help!