Thought this was a good article, and may demonstrate to many that the lubes Merc specifies for our Engines are indeed engineered specifically for them...Oil is not oil (well, actuall Oil itself as it comes out of the ground is basically oil -- although there are differences from whence it came), but what is done after it leaves the well head and before it gets to us consumers can vary greatly in quality, cost, and protection/function. Happy Reading.
https://www.boatingmag.com/how-marine-oil-made/