Not tryin' to be a smart-azz or anything (well... maybe a little), but at temperatures above 30° you can run 20w-50 in 'em... LOL
I run 10w-30 in all the small engines until temperatures drop permanently into the teens and single digits (New Years or thereabouts), then I switch to 5w-20 for a couple months.
Synthetics?? I don't pay attention... just buy whatever's on sale the cheapest at the time, sometimes it's a synthetic or a blend, sometimes it ain't. In small engines it don't much matter, the oil needs changed every 50 hours or 90 days regardless. I just use the 90 day schedule when it's being used... 'bout the only thing that gets used year 'round is the little tractor so it gets new blood 4 times a year, most everything else 3 times. I figure I can't be doing wrong; the little tractor is a 1968 Sears, still fires right up and runs good in any weather... and don't use enough oil to force me to add between changes. Really, in small engines, if it's time to add oil, I figure it's time to change oil... just can't see adding a ½ pint when most of 'em only use 1½ - 2½ pints total.
