absolutely correct Outlaw...
All modern day shelf oils (including the new diesel engine oils) have all the zinc and phosphorus stripped out them because they contaminate and plug up the platinum filter screens in catalytic converters (yes, even on diesel engines)..!
All modern car engines have components and designs that do not need the anti-shock and anti-wear benefits of zinc and phosphorus.
But, all flat tappet hydraulic and solid lifter engines absolutely need it...! This includes all small engines found in lawnmowers, generators, snow blowers, tillers, etc., weather water cooled or air cooled doesn't matter...
There are several companies now that make and sell "hot rod" or "classic car" oils because there is such a huge need and demand to keep these older engines protected...!
You also really need to get good Briggs & Stratton or similar oil designed for your lawnmowers and small engines... there IS a difference...
As a small engine mechanic I am seeing many, many premature wear failures in lawnmowers and small engine due to wrong oil failure.
As a race engine builder I am seeing the same as described earlier with cam and bearing failures.
I wish there were national TV ads warning people of this important information...? Jim