I purchased a Toro recycler self-prop mower in Jan 2012, and used it through that mowing season. Fired it up two or three times in 2013 after changing the oil and it started running funny.
Checked the oil, nearly no oil. Strange. Not good. Filled with oil, started up, blew white smoke for several mins.
then stopped. Finished mowing and took to the shop next day - Abshire's in Lafayette, LA.
Told that "improper air filter maintenance" had voided my warranty and that I may as well leave the mower with them so they'd waive the 35 dollar tear-down fee.
Not sure what air filter maintenance is expected, but apparently these Briggs engines are a bit more sensitive these days. My poulan ZTR went 2 years with a single filter, never gave any issues.
Review about: Briggs And Stratton Engine.
Monetary Loss: $320.