If it's the 9 inch harp machine it uses a regular domestic machine needle. The best I've found for fmq are the Superior Titanium Topstich needles made by Organ. The 80/12 size would be correct for a 50 wt thread. The topstitch needles have a deeper throat groove and a bigger eye - this makes them less likely to snag the thread and makes the thread "flow" more smoothly.
You may also be unconsciously pushing harder when sewing away from you. Try to focus on sewing the same speed at all directions. Don't grip the handles too hard. Other things to try - increase your machine speed and/or slow down your machine movement.