i've used 5/30 synthetic in almost all of my small engines (unless calling specifically for something else) and never an issue. i usually buy a 5 quart jug of a synthetic 5/30 and that's my small engine oil. Well, i was going to get a new lawnmower this year (push mower) but new windows in the house and a new snowblower this last winter i'm hoping for 1 more year out of my old trusty grass chopper. the last 2 seasons it occasionally blows some blue smoke at start up (not all the time). had it looked at back then and the guy told me the rings were just getting worn, and if i was planning on replacing it anyways no big deal, when shes done just let her go (didn't pay much for it, it's a poulan with a briggs engine). i've mowed twice now, a week ago and today. today i noticed after it warmed up just a slight amount of blue smoke while running... which is kinda new. is there a different type or weight of oil that can help out a little bit? i know it wont fix the problem, just need this mower to last 1 more season if possible