Next to the cylinder there should be an electric motor with a couple of wires coming out of it. On the other side you should see a reservoir for the hydro oil. I'm generalising here, haven't looked at a small Evinrude for a long time.
You could connect a battery to the wires coming out the motor, both positive, 1 for up, 1 for down, earth to the engine block.
Or much easier there should be a big screw located around the reservoir housing (not the fill/level plug) which operates a release valve. Loosening the screw will allow you to manually let the engine up or down, tighten the screw to lock it in the desired position.
As I said, I don't know 'rudes very well, I could be just making a t*t of myself