what is Briggs & Stratton's engine life claim? (usually there's a sticker with tiny print indicating that hour use spec.)
Once a year drain is what I do, like mentioned above. Engine goes 12 years, give or take, before a bad rod or high oil usage forces
a swap. (Snapper self-propelled walk-behind, early eighties 6 speed Hi-Vac) I probably would buy the new 'no oil change' B&S, for use on my
antique, but I'd still drain every 12 months, & filter & plug & blade check/swap. Why would I neglect my own equipment? I'm not that lazy. Yet.
edit: seems the no oil change required engines have a two year consumer warranty.