In my experience there are two main reasons that cause a small engine to burn oil. The easiest fix is if the oil has been overfilled which is fixed, of course by draining some of the oil. The other more typical problem is not changing the oil and only adding occasionally. If this is the case then your rings are probably shot. If you have some mechanical ability and a few special tools , such as valve spring compressors and ring compressors, and a decent place to work you might do this yourself for about fifty dollars worth of parts. Repair shops rarely replace rings as their bench charge is so high, sixty or seventy bucks an hour, that they usually want to short block it. A short block might run a couple of hundred dollars. Sometimes you can get a little more life out of the engine by just changing the oil if you haven't done it already. Run the engine a little until warm to get all of the impurities mixed into the oil before changing. You can get repair manuals from briggs and stratton or tecumseh that have pretty good step by step tear down and rebuild directions. Also b/s website has blowup diagrams to look at or print for replacement part numbers.
Steve Cates, December 2007