A list of Schaeff dealerships.
Couple of suggestions. E-mail the Schaeff corporation and ask their engineering/archive/historical department it they have any information on your lift
Contact the Schaeff dealership in your area, asking for same information.
Starter for Onan engine. Onan parts are still available - expensive. The starter should/will be still available. It will take some research. Typically the starter was used by several engine manufacturers. Look for the same starter but used on say a Briggs engine - will be cheaper.
parts will/should be available - after identification.