Theres a little crank,#24 that pushes the pin, #23 of the clutch. Crank is fitted to the shaft by two flats. A cotterpin #29 prevents the shaft comming out the engine, this could have dropped out, check by pulling on the outside crank.
http://www.ronayers.com/fiche/300_0039/clutch/clutch.cfm?man=su&groupid=7160&...Suggest to have a look inside to see the damage.
You have to open it up anyway to do the repair
Greetz
Kropatchek