Briggs & Stratton’s documented eight-digit engine Code contains a six-digit date followed by two plant-and-assembly digits. In the manufacturer’s example, 99011556 means January 15, 1999: 99 is the year, 01 the month and 15 the day; 56 is not part of the calendar date. Read the Code field of the Model-Type-Code stamp, rather than treating the Model or Type as a date. This dates the engine.
A generator can be assembled later and has its own equipment label, so use the generator’s label when asking about the complete unit or ordering equipment-specific parts. Briggs identifies 1965 as the start of this Code dating method. Earlier engines need its antique-engine dating reference. If a stamp is damaged or the characters do not fit the documented format, send a clear photograph of all identification fields to a Briggs dealer instead of forcing a date from an unrelated number.
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What this covers
- Briggs & Stratton standby-generator engines carrying a Model-Type-Code stamp with a 6-digit Code portion
- Reading the Code as two-digit year, two-digit month, two-digit day, in that order
- Engines built from 1965 to the present, per Briggs & Stratton's own page
What it does not cover
- ×Briggs & Stratton engines built before 1965, which used a different identification method not covered here
- ×A guarantee that the engine's date matches the standby generator system's own final-assembly date — they can differ
- ×Any Briggs & Stratton engine whose stamp is hidden under a decorative cover that was not removed to read it
Try in this order
0 of 4 completedFind the engine stamp
ReversibleLook for Model, Type and Code on the engine. Briggs notes that some overhead-valve generator engines have a decorative cover over the rocker-cover stamp. Shut down and follow the equipment’s safety instructions before accessing it.
Copy the complete Code
ReversibleKeep the fields and their labels together in a photograph. Do not substitute the engine’s emissions-label numbers or the generator’s separate serial number.
Split the documented eight digits
ReversibleGroup the Code as YY MM DD PP. The first six characters give year, month and day; the last pair identifies plant and assembly line.
Check the equipment question
ReversibleFor an engine-age question, retain the decoded engine date. For a generator warranty or whole-unit age question, supply the equipment label as well and ask Briggs to confirm its record.
Evidence ledger
Sources behind this answer
Exact questions
Questions about Decode a Briggs & Stratton standby-generator engine date code
Does the Briggs Code date the complete generator?+
It dates the engine. The equipment has a separate identity and can have a later assembly date.
Are the last two Code digits the day?+
Not in the documented eight-digit format. The day occupies positions five and six; positions seven and eight identify plant and assembly line.
What if the engine predates 1965?+
Use Briggs’s antique-engine dating reference rather than applying the later Code rule.
Can I identify an engine from its emissions label?+
Briggs warns that emissions-label numbers cannot substitute for Model, Type and Code.
Where can an overhead-valve generator stamp be?+
Briggs identifies the rocker cover as a common location, sometimes behind a decorative cover.
What should I send a Briggs dealer?+
A readable photograph of the complete Model-Type-Code stamp and the equipment label, with the question you need answered.