OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines 12,5 briggs

The important thing is the recommended substitute engine, which AVB has access to, I don't. However for light reading in the meantime, here is the Illustrated Parts List for your blown-up engine:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6ntzHVJ1DajI.pdf

Here is the Operator's Manual:
http://bsintek.basco.com/BriggsDocumentDisplay/mssAIQ-K_ny7tH217FzoPu.pdf

That engine was manufactured on 25 June, 1990.

The separated 01 is called the Trim number, and is an offshoot of the second number (the Type). The first number is the Model, and the third number is the Code, which tells you the date of manufacture.