hey guys, i have posted here in the past about my usage of mobil 1 ss 10-30 in all of my outdoor equipment. this includes a honda mower w/ the 5hp ohv motor, a lawn boy silver series mower w/ the 5hp tecumseh 4 stroke, and a yardman vac, shred, mulcher. while i still use it in the honda and briggs, i tried shell rotella 15-40 in the tecumseh. this mower runs great and doesn't use oil. change the oil in it probably 4 times a year as it gets quite a bit of action. the motor was broken in for the first few cuts on qs hd 30wt and then right to the mobil 1. i was quite sure there would be no crud in the engine, having been using a good synth, but i couldn't beleive the color of the oil when it came out. jet black. just goes to show about the fantastic cleaning action that the 15w 40 oils have. i'm sure that the other brands such as delo and delvac would do just as good of job, as well as the penzoil 15 40 as it seems to have quite a bit of the moly in it which i beleive my rotella doesn't. penzdude