First, check to see if you have a brand new SCHMETZ needle CORRECTLY inserted and 50 weight "sewing machine thread", not hand sewing thread CORRECTLY threaded through the machine and bobbin and try sewing again.
It is very easy to set the timing on it, you just need to get a few expensive specialized timing gauges, tools, a repair manual for that model and a few years experience repairing sewing machines...
If this fails, have it repaired by someone who knows what he is doing.
Moss Limbayter
May 2009