I have a 79 briggs 11 aluminum bore that was on a Dixon zero turn mower doing about 3 acres from 1980 to 2011. Mower was beyond repair but saved the engine for parts. I did take off the shroud every 2 years to clean the chaff and dirt. It was just beginning to burn oil, needed some added every 4 hours. Ran on 10W40 it's entire life. Got about 75 to 100 hours a year depending on rain. 31 years, probably about 2500 hours Carb shaft was so worn it no longer idled worth a crap. Original plug, it always ran good and if it ain't broke. One starter one fuel lines and filter. Many blades, many deck bearings one seat, one reman transmission. Zero turn mowers work the engine much harder than tractor style mowers and showed it little mercy. I would probably still be using it if Husky had not bought Dixon and discontinued transmission parts I needed.