Another article in Boating Magazine shows that the 4-strokes cost surprisingly MORE to operate than a DI 2-stroke!
http://www.boatingmag.com/engines/ou...MjQ1NDU1MzI5S0 Even with the 2-stroke using expensive full synthetic oil, the relatively small savings in 4-stroke fuel costs isn't nearly enough to offset their higher maintenance costs. And this doesn't even consider the cost of the required valve lash check/adjustment on the 4-strokes at 500 hrs. If they had run the analysis for 600 hrs instead of 300, the operating cost difference would have been even more obvious!