I have this machine and when the thread breaks when FMQ it is usually the wrong size needle for the thread. I switched to topstitch needles for all my sewing and most of my thread problem have gone away. I use Organ topstitch needles. I use all brands of thread. Superior threads has a sample pack of each size so you have all you need to try. Here is the chart I use for all my sewing:
1. Topstitch #70/10 for very fine thread
2. Topstitch #80/12 for fine threads (50 wt.)
3. Topstitch #90/14 for medium threads (40 wt.)
4. Topstitch #100/16 for heavier threads (30 wt. and heavier)
Here is the link to great thread/needle info:
http://www.superiorthreads.com/education/