First sentence is true. Second sentence is partially true. Air cooled engines are less efficient than water cooled ones, something about the combustion temper

First sentence is true. Second sentence is partially true. Air cooled engines are less efficient than water cooled ones, something about the combustion temperature and running rich. Two strokes are actually more efficient than 4 strokes. Overall though, a small air cooled 2 stroke will be less efficient than a large water cooled 4 stroke.