My brother swears by synthetic oils when it comes to every single vehicle that he owns. He would never put something that was not synthetic into his car and he wouldn’t do that to his boat either. He loves the way that synthetic oils work and is not willing to sacrifice the benefits that he sees in these oils, just to get something that is slightly cheaper.
For his boat he will only use Evinrude XD100 oil. This oil is specially formulated to burn clean. As a big supporter of environmental awareness, this is very important to my brother. He loves the performance that the oil gives him and the lack of ash, smoke, and unpleasant odors. He feels as if he is getting the best deal by using this oil.