I am trying to resurrect my mom's old Singer (Model 758), but I'm having a problem. It seems like the fabric is not feeding through the machine very well, so I end up with bunched up fabric around the stitches. If I pull the fabric taut with my hands at the front and back and sort of pull it through the machine, I can get nice stitches, but this is not an easy way to sew. I tried adjusting the pressure dial for the presser foot, but this did not help. I am new to sewing, so maybe there is something I a missing. Any advice would be appreciated.
Oil the thing top and bottom, every moving part with a drop or two of sewing machine oil. Run it threadless at high speed for a few seconds and oil again. Wipe of access. Gunked up machines run out of sync and behave like you describe.
The feeding "teeth" can be worn out if it's a very (very) old machine. Clean it thoroughly. There may be some amount of lint under these teeth, and in the feeding mecanism. Most parts can be unscrewed and inspected.