Helped a neighbor lady with a new lawnmower she just bought. Adding oil to the engine, the owners manual stated that you never have to change oil, but said that you must add oil when it gets low.:surprise: So after that, I put gas into the tank. And on the cap, had info saying that it is alright to use ethanol gas of no more than E15. I don't get it! Does this mean that ethanol based gas will not harm this engine? And what about the oil. Does this thing by design purposely use oil so that by adding oil keeps the oil always new?