decky

I have been sewing on my 301 and all of a sudden the stitches have started too pucker. I re threaded and and took the bobbin out and back in. It if still puckering. Any ideas on what could be wrong?

quiltsRfun

Try adjusting the tension.

Cari-in-Oly

Time to clean under the needle plate and check the presser foot pressure.

Cari

sews

Time for a new needle?

NJ Quilter

Or perhaps a tiny bit of thread stuck in the bobbin case. I would start with cleaning then a new needle.

miriam

check for burrs

Monroe

All of the above, but since you've already rethreaded I'd start with a new needle and checking the bobbin case first. I love Miriam's line above- Never let a machine know you are in a hurry. Last minute Christmas sewing perhaps?

ArchaicArcane

I would first like to know what side is puckering? Can you post a pic? Is the bottom thread tight or the top thread? Which one is the thread that is deforming? the fabric? That will tell you what side to address.