Oh, MIckey2, you are a genius! I checked the foot and it is a Singer snap on, has the correct J on it, but it may indeed be the wrong one. I've checked all the other things like clean, oiled, took out and replaced the bobbin holder, etc. Next I'm going to check the feed dogs and make sure all the parts it says are there are actually there. I might try a shim under them and see if it helps.
And this weird machine doesn't have a way to lower the feed dogs, it comes with a little plastic plate to put over them to block them. Really strange.