The engine was manufactured on 3 January 1988. It is 8 cubic inch displacement (130 cc), side valve design, of B&S's third design generation, with a horizontal crankshaft and a PulsaJet carburetor. It has a ball main bearing on the output shaft side, and a rewind starter. This engine is an I/C ("Industrial/Commercial") model which means it has a cast iron sleeve in the cylinder rather than B&S's usual aluminium bore.
Here is the illustrated parts list:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6ntACVJ1DajI.pdf
Here is the operator's manual:
http://bsintek.basco.com/BriggsDocumentDisplay/flivAJX-nfBhU7y.pdf