Well, I have to offer thanks to the gods of B&S once again.
Was going to mow MIL's yard, but the mower (that was resurrected with a pull or two after a decade and a half slumber) would start, run 10 seconds, then die. I thought it wasn't picking up fuel, so I filled it all the way up, no joy.
So, while futzing with it, I figured I'd "start it racecar style' as we used to call it back in the day, so i removed the filter...hmmm..carb looks uber clean...prine, prime, prime, pull...boom, ran like a top. Shut it off, looked at the filter, and it was grodewy. Being to lazy to run to the hardware store, and figuring a little water would help knock out some carbon deposits, I hosed the filter off, screwed it back together, yanked the cord, and mowed away.
I'm wondering now how many mowers tossed out these days could just use a simple tune.