Fixed!
It was indeed the hook timing. just had to move the needle bar a bit and bam! works like a charm.
I love these old tough rugged machines. They're all like "just push that piece back in place" kinda solutions.
In my case, I don't have a screw holding the needle bar in place. So i put the machine into the right position and used a stick an a mallet to push it into the right position.
back to repairing the swimsuit!