I have the Baby Lock Jane, which is the larger duplicate of your machine..made by the same company and looks identical just bigger - no problem with my tension in the months I've been using her. my feed dogs go all the way down when I have it on the fully dropped setting - there are three or four settings (not sitting at my machine right now). As far as the curling threads - try putting the thread spool/cone in a cup at the back of the machine then run the thread up and through the channels to see if that takes care of that issue - I have not experienced that situation myself. At the very least, try calling the repair shop to see if they can give you any tips to avoid a shop visit.