tension would be fine tuning.
what you have is a damaged needle or wrong size of needle.
if you have a spare needle that is NEW please put that in and rethread.
Check the size of the needle and make sure it is a 10 or 12 or 14, maybe even 16 if you are not using a waterproof fabric
with the thread you are using, probably 12 or 14 would be best
The pic that you show looks like the thread is thrashed or something.
Either the needle is too small or it is damaged.
A needle only lasts so long and normally you can wear it out with only an hours worth of sewing (even more so if damaged)
edit: as long as the needle is new and the threading is correct on the machine, there may be a burr on the bobbin or any linkage thereof.
Start by changing the needle 12 to 16 and rethreading
Bookmarks