I don't know why you need a manual, they are simple and if parts are needed any of the dozens of parts suppliers online will show you a parts diagram and some still have parts.

Parts tree, repair clinic, jacks small engine and the list goes on and on.

But the first thing you should do is see if the engine is good, other wise it scrap metal. Do a blow down compression test to see if the rings are shot or the valves are shot. Take the Carb and see if it's rusty, if so odds of cleaning it to work are slim. A manual isn't going to show you how to fix a thing, only how to do Preventive maintenance, how to start it and use it. A service manual is what you need, and you'll need to dig deeper than posting a request here.