A lot of people ask what the differences between most oils are. It is true that, at its core, most oils do the same exact thing. They lubricate the engine and keep it from overheating. Some oils do it better than others because some oils are fully synthetic and other are just semi-synthetic. Manufacturers suggest that you use their specific brands of oil for their engines but what happens if you use something else?
Yamaha recommends that I use their specific brand of Yamalube Oil on my outboard engine. They say that their oil is specially formulated for their engines and using something else might have negative impacts on the engine. I heard from other people that they don’t like using the more expensive oil because the cheaper oil does pretty much the same thing than its more expensive counterparts. My preference is to stick to what the manufacturer tells you to avoid unnecessary harm to a very expensive piece of equipment. I would much rather spend a few extra dollars on motor oil than to have to replace my outboard engine. But to each his own, I guess.