If it's a second hand machine, try taking off the little brushes under the carriage, lots of fluff gets wedged under them and that stops the wheels from turning. It could be that you have put the carriage onto the machine incorrectly. Where have you oiled the machine, on the running rails on the machine and the runners under the carriage? Another maintenance job is to remove all the needles, bath them in surgical spirit mixed with a little drop of oil, clean and replace them. In addition, it could be that the sponge bar under the needles needs to be replaced - the sponge goes hard after a few years - you will need to remove this to take out the needles, so you can check it then.
Brenda, July 2009