Joey would have piped in yesterday but he was in the ER most of the afternoon.
First I'd take Greywuufs suggestion and go to to TFSR. {
http://www.tfsr.org/publications/tec...machine_manual }. Use their instructions to completely go through that top tension to clean, adjust and make sure it all there in good condition.
There is more to it's adjustment that just twisting the knob.
As I looked at the pics one of the disks looked like it had a burr on it near the edge. So check them for wear, rust, pits or other defects.
Most clones are built so the hook to needle timing can't be adjusted. If it's out then something major is wrong with the machine.
Joe