A guy I used to work with has a push mower to get the areas that his rider won,t go. He has had it for 10 plus years and just adds oil and gas as needed. Never changes the oil ,never sharpens the blade ,never puts stabil in it. Always starts and get jammed under the shrubs, and around trees, and fence post. Beats the crap out of it ,says it is easier than dealing with a weed wacker.Heck people have been doing that for 60 years...
Do you suppose they put bad rings in them or perhaps notch them?Briggs and Stratton claims that their new engine design "runs at a cooler temperature, allowing the oil to remain useable."
I own one, and mine burns some oil. It has since new. My theory is that it burns off the old oil, so that when the owner would check the oil, they would add new oil, and this cycle would continue as the oil gets burned.