That is a Briggs and Stratton engine, 6 cubic inch (100 cc) displacement, of the first design generation, horizontal crankshaft, Pulsa-Jet carburetor, plain main bearings, with a rewind starter. It was made on 27 August, 1975. Being pre-1982 it will have breaker-point ignition.
Unfortunately Briggs and Stratton does not list an owner manual or parts list for that engine. If you want a full workshop manual for all of the single cylinder side-valve Briggs engines of that period, you can download it from the engine manuals section (subscription required). The most suitable manual is the one labelled "Briggs and Stratton Service and Repair Instructions 1984".
