Also, if you do push in you can change where the numbers are lining up on the tension dial (where the little peg goes in). DH and I have had to mess around quite a bit with getting the tension dials set right so that with the bobbin tension good - the top is set in the middle. DH normally takes the tension dial completely apart to clean.
We had to take one apart several times before we got the numbers in the right spot. Was a similar problem - setting it all the way to 1 and was still too tight. Dh was trying to compensate by tightening the bobbin tension. He could still "jerk" but he had to give it a rather stiff jerk. I tired it and said "no" so back to the bench the machine went. He eventually got it prefect, and now he knows something else to watch for.