Hi mickt, in my opinion, it is not the safety clutch. The safety clutch is doing it's job.....popping out if there is a problem. In my opinion I think it is your stitch length mechanism that is causing the problem. I have seen many machines where the stitch length mechanism is frozen. As Gregg says, it should be looked at by a good mechanic like Bob Kovar or someone with his knowledge. I have done this type of work also, but I am in California, so it would be worth it to ship the machine to Bob, and he can repair it and have it taken care of once and for all, yes it will cost $100-$150 to ship it back and forth, plus the repair, but it will last you 20 years. Thanks, Steve