"2-stroke oil and mixture are
"2-stroke oil and mixture are mainly a lot of compromises.
The older engines with bushings an not needle bearings needed 4% oil-mix in general, the newer ones 2% mix was/is sufficient. Then with even better alloys and materials some chose to go for 1% as recommendation. In general most modern 2-strokes (with needle bearings) will run on 1% without problems, however they will not last long NOT running on 1%. Use Your Evinrude/Johnson daily and You may run on 1%, use it once a week or even in longer intervals it will probably corrode to pieces and suffer premature wear. Not from the running itself, but from the excessive wear at each start when there is no oil left from last running.! The same goes for Yummies.
Low ash, no-ash, no smoke and so on is another part.
The best, for the engine, would be that the oil is no smoking. That on the other hand means it is not burning and the oil goes straight back into the sea unburned! The more smoke, the less oil goes out, but in general the more carbon build-up You will have in combustion chambers, exhaust systems etc.Technically a bio degradable oil that does not burn and is concentrated on lubrication only might be the best, but even the most expensive to produce. No smoke, less carbon, environmental friendly. On the other end You have the smoking ones that burns the most. These oils are often mixed with 'solutions' to make them burn (low flaming point), leaves no oil-trace, but on the other hand has less lubricating abilities pr unit oil. Pick Your choice what You want, but You can not have it all in one bottle.
(I leave the hi-tech injected engines out of the discussion.)"