Welcome to IIS Pascal
Now the nice bit is over we get onto the problem. Basically that mount is going to give you grief forever. I have never got good results from all the ones of that type I have played with. After saying that I have had "better" results when the scope is balanced so you can adjust it easily.
Find yourself a couple of small magnets and put them on the OTA (optical tube assembly) (the tube) one infront of and one behind the pivot point. Move them till the tube is balanced and stays in position with the screw on the silver rod only just working. You then should be able to adjust the up/down movement easily by hand but you will still have a wobbly mount.
Give it a go.