Thanks Deejay, I missed the 2 bolts and thought it just had a location collar. So you tend to have an exciting time snatching the crankhandle out of the socket after start-up? I can't see an over-running arrangement that allows the handle to disengage from the socket. A spring-loaded pin in the socket would do it, if it has one.
I can remember having to do a precision job of making a crankhandle for a Lister once: it had a spring-loaded pin that engaged a keyway in the end of the camshaft, and pushed out on overrun, but if the crank was slack on the end of the camshaft where it engaged, they were reputed to grab and spin with the camshaft. Since it was a big two-handed handle with a long overhang, having it spin would be more exciting than I preferred.
