Briggs & Stratton Engine Identification Methods

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1. MODEL INFORMATION & NOMENCLATURE

Every Briggs & Stratton engine has a basic model letter or number such as A, WM, ZZ, 5, 23, etc. This will be found on the metal nameplate if it is present on the engine. The early F Series has the Model & Serial number stamped into the crankcase. Early engines (up to somewhere in the 1940's) have a brass plate on the shroud and later engines have a zinc or aluminum plate on the cylinder shield. Engines having special features are identified by additional letters or numerals assigned to the basic Model Letter or Number such as AL, 8R6, NS, etc. For Example the 8R6 is a model 8 engine with a 6:1 reduction gear and the NS is a model N with a suction carburetor. An explanation of these suffix letters is given below.

LETTERS FOLLOWING BASIC MODEL LETTERS

G	Generator				H	High Speed
L	Aluminum Parts				P	Direct Crankcase Mounting
R	Reduction Gear				M	Marine Conversion
S	Suction Carburetor 			T	Marine Transmission

LETTERS FOLLOWING BASIC MODEL NUMBERS

B	Ball Bearing				C	Automatic Choke
D	Power Takeoff Revolves CW               F       Flange Mounting
H	Horizontal Engine			P	Fuel pump
R	Reduction Gear				S	Suction Carburetor
Briggs & Stratton engines can be dated by several methods. These are listed below in order of their accuracy.

  1. If the model and serial no. are known, the manufacturing date listings presented elsewhere on this website will give the month of manufacture.

  2. A date code was used on most die cast flywheels and magneto plates. The last two digits of the year are shown in one cast in depression and a letter representing the month is shown in another. The months are lettered in order, ie. A = January, B = February, etc. Based on comparison with serial numbered engines, these dates are accurate to within several months, assuming that the parts are original to the engine. I have also found that the same type of date code is stamped into the laminations of some earlier magneto armatures.

  3. A rough estimate can sometimes be made by certain engine features such as external vs. internal breathers and oil systems. A solid knowledge of Briggs engines is required to use this technique.

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