There's a couple things you can try. Go up to a size 100/16 needle TOPSTITCH needle. Topstitch needles have a longer eye, and it gives your machine more time to catch the thread. Another thing to do, if the timing is off, is to move the needle bar position to the left or right. That can put the hook closer to the eye, to catch the thread.
If you could take it to the shop, it's incredibly easy to adjust the needle/hook distance or needle bar height on those types of machines. If you got the right tech, they should do it pretty cheap.