Briggs & Stratton 83100 Operator's Manual page 12

Intermediate:
Engines at or less than 80 cc displacement are certified to be emissions compliant for 125
hours of actual engine running time. Engines greater than 80 cc displacement are certified
to be emissions compliant for 250 hours of actual engine running time.
Extended:
Engines at or less than 80 cc displacement are certified to be emissions compliant for 300
hours of actual engine running time. Engines greater than 80 cc displacement are certified
to be emissions compliant for 500 hours of actual engine running time.
For example, a typical walk-behind lawn mower is used 20 to 25 hours per year. Therefore,
the Emissions Durability Period of an engine with an intermediate rating would equate
to 10 to 12 years.
Briggs & Stratton engines are certified to meet the United States Environmental Protection
Agency (USEPA) Phase 2 or Phase 3 emissions standards. The Emissions Compliance
Period referred to on the Emissions Compliance label indicates the number of operating
hours for which the engine has been shown to meet Federal emissions requirements.
For engines at or less than 80 cc displacement:
Category C = 50 hours, Category B = 125 hours, Category A = 300 hours
For engines greater than 80 cc displacement and less than 225 cc displacement:
Category C = 125 hours, Category B = 250 hours, Category A = 500 hours
For engines of 225 cc or more displacement:
Category C = 250 hours, Category B = 500 hours, Category A = 1000 hours
80008114 (Rev C)
12 BRIGGSandSTRATTON.com