DOES THE TACSEW T1718 MACHINE SEW IN A ZIG ZAG

Try this site

https://searchmanuals.net/search7/?keyword=%2Bmanuals&gclid=Cj0KCQiAtvPjBRDPARIsAJfZz0raFHZpS-4d0R25posASnlrF4Mbma-3QWbGHbwEbcKsLj2Bbnl1dFwaAnTnEALw_wcB

Sounds like the pattern selector is bound up. Make sure your zig zag is set to zero when changing patterns. That may help.

Replace the needle anyway, it's probably blunted now. Also narrow the zig zag width. But your machine needs adjustment. Take it in for a good clean and repair.

it's possible the zig zag gear or cam could be worn or damaged
and the machine should be checked to see for sure what's happened.

since you bought the machine at a state sale it would probably be a good idea to have the machine serviced.
you should be able to go from straight stitch to zig zag with out any problems.
if you move the dials or knob & the machine will not do a straight stitch then it needs to be checked

contact a tacsew dealer or sewvacdoctor.com

You have the machine set for blind hem stitching. Change the stitch selector to stretch stitch, which is a single, in line stitching zig zag stitch.

Cheers,
Embroidery Services
San Diego, CA

Sounds like your zig zag stop is out of position, simple adjustment for a tech.

Machine will not sew forward. It will sew backward on zig zag stitch. Could this problem be the reverse switch spring broken?