Take a tip? The recoil starter cord is readily available from any mower outlet, and this is all you usually need - the trouble is fitting it as there is a powerful spring in the recoil mechanism which can be a real pain if it springs clear and uncoils. So, take the complete housing to a local lawn mower shop and get them to do it - not too expensive and saves loads of grief. They'll charge you for 15 minutes labour, usually. I charge £12, including the starter cord.
John
May 2009