Deejay, the symptoms he has described (smoking, and blowing out oil) are both probably due to worn piston rings. If it is a Briggs & Stratton, that is a minor problem and on its own is fairly easily fixed by replacing the rings. However if the bore is damaged (usually due to having been seized up at some time, after running out of oil) he will need to replace the piston and cylinder at the same time (hopefully with free ones from a nearby junked B&S engine). I think what I would be doing in his place is identifying the engine (if its a B&S, and he gives us the numbers stamped on the air cowl, we can do that for him). If it is a B&S, he should consider its overall state of wear, to see if a minor overhaul will be sufficient. If it's a Kirby-Lauson (Tecumseh) I'd junk it: lousy engine, and parts too difficult to get except for collecting purposes. B&S engines that haven't broken the connecting rod are usually fairly easy to tidy up sufficiently to run well for a number of years, using second hand parts from wrecked mowers except for gaskets, fuel pump diaphragm, and rings, which of course should be bought new.
