At the top of the treadle fly wheel is a lever, treadle the machine and push the lever and it will throw the belt. In all probability if the machine has been kept indoors, all it needs is a good oiling and some treadling. That is all the servicing these machines really need. My 15-88 treadle is the same as my moms 15-91 except mine has a treadle and no light and hers has a motor and a light. These basic machines are pretty much the same, they just need sm oil.