threading is easy,just follow the line.coming from right behind machine thru guide and then towards front thru tension unit and downup to takeup spring where you go right and then up towards take up lever,from left to right thru takeup lever and down thru thread guide at needle bar then thru needle eye from front.just make sure needle is correctly inserted,eye to front and cut at back,also check top and bottom tension as your explanation almost sound like tension problem
johan
September 2013