The oil is pretty expensive but after the first 10 hours or so on the engine it barely uses any. It also helps keep less wear and tear on the engine (so I'm told). My boat when filled up weights like 8500 lbs. I run my twin etecs at 4200 rpms, cruise at 38 mph. And get 3.5 mpg.
This post was edited on 7/11 at 5:03 pm