Briggs and Stratton engines are identified with a MODEL, TYPE and CODE number system and take the form of the example below.

• The MODEL number is either 5 or 6 digits which may contain letters
• The TYPE number is 4 digits followed by a trim extension of 2 digits. Letters may be used in the extension
• The CODE number is the machine's serial number. The first two digits are the Year of manufacture, the next two the Month
  and the 5th and 6th are the Day (the example above was made on 7th July 1999)

The numbers can be in a variety of locations depending upon the engine but are generally to be found either:-

Stamped into the front, top or side of the main cowling. These sometimes need corrosion removed or plastic cowlings lifted slightly or air filter removed to see.
Stamped into a plate over the exhaust or a bracket in front of the carburettor.
Etched into the crankcase side behind the carburettor or behind the exhaust.
Etched or stamped into the edge of a rocker cover. These sometimes need corrosion cleaning off to see.
Etched into an aluminium plate riveted to the cowling. These can sometime be forced off. If this has happened, there will be two small pulled out rivet holes.
Etched into the crankcase at the rear.
Etched into the plastic fuel tank (Quantum Mk1 Model 100708)