Nancy,
I don't have the Singer specs for the 301, if there is any, but put a factory foot on the machine and check the clearance between the bottom of the foot and the needle plate, feed dogs down. It should be over 1/4". I've had several machines that had the presser foot bar set too low.
The spec for the 401A and some others is .295". Ours was just under a 1/4" (.250"). Surprisingly that small distance made a huge difference in how the machine worked and fed the fabric.
The presser foot height will also affect the way some attachments work. Or so the service manual says.
Joe