Part, 235372, 538235372, for McCulloch Mac 538, 538e, 539, 539e, 540, 540e, 542, 542e, 545, 545e, 930, 935, 940 Chainsaws and more. ( This is the part which fits inside the starter housing and spins when you pull the cord to engage the flywheel pawls ).
eBay