Back in the summer of 1985, we bought our first house. Here's a picture from space as it is now
As a pre-wedding present back in early 1985, our in-laws bought us a Craftsman lawnmower with a 2.5HP Briggs engine. Our yard was 65 x 135, on a corner lot, so we had another 200' of tree lawn 6' wide. I mowed at least once a week, 7 months a year, sometimes twice, because I had a sprinkler system and fertilized. It was the nicest lawn on the block for many years. We moved out in early 1996 (we actually put it on the market Memorial Day, 1996, because there is a parade in front of the house that day every year, and we got an offer the next day and sold it). So, we'll say 1 time per week, times 4 weeks per month, times 7 months per year, times 11 years. 1 x 4 x 7 x 11 = 308 times. Then I used it to mow a small enclosed area and as a trim mower at our new house until just a few years ago. As I recall, it was 29 years old when the deck failed and I bought a new mower.
In the 29 years I ran that mower, I never, ever, changed the oil. Not once. Ever. I'd just check the fill plug, and top off if necessary. I doubt I put 2 qts in it total in 29 years. It had the original air cleaner. I'd just tap it out on the ground a couple times a year. I think I may have changed the spark plug once and that's it. And the best part.... it started on the 1st pull every year after sitting in the shed all winter with 1/2 a tank of 10% ethanol gas, untreated. For the last 4-5 years of its life, we'd have a 1st pull ceremony each spring to see if it would go. I'd make the wife and kids come out and watch. I'd check the oil, top it off, top off the gas, push the primer bulb about 20 times, hold down the handle and pull and rrrRRRRRRRRRRRRR off it would go. I'd just shake my head and laugh.
I still have that engine. I removed it from the deck before I trashed it. I could not bear to throw out the most dependable, consistent, engine I ever owned. It has a place of honor in my garage.... somewhere under all that other crap I've saved. :laughing:
So, I do not doubt that a small engine manufacturer would now come up with this add oil, don't change it, policy for this pressure washer. Its been a long time coming. The engine will outlast the pump, most likely. And it probably won't be operated 10 hours per year total, on average.