I was going to buy a ride on mower one time and had it all arranged to inspect and pick up. The first thing I noticed when I got there was the whole engine was plastered with oil. This guy was under the impression that modern fuels are no good for 4 stroke Briggs engines because "it all contains Ethanol now", so he was convinced you have to add lots of oil to the fuel to stop engine wear. He was really pouring the oil into it. Of course when he kicked it off I could hardly breathe for smoke fumes. Told him I suddenly wasn't interested and he asked "Why not?". I mentioned I was a bit suspicious of all the oil he was putting in the fuel tank, but he did not have a clue what I was talking about. Evidently he has always mixed oil with his fuel to run all his engines, 2 or 4 stroke. They all get the same fuel. LOL!
All these tales of oil added to four stroke's fuel tanks could explain why the Briggs powered Scott Bonnar rotary I found years ago which spewed white smoke like Puffing Billy, but otherwise started and ran fine. I thought how can an engine sound so healthy but smoke so appallingly and then the aha moment and alas the smoke cleared very quickly once I replaced the fuel!! I had myself a top mower.
