drainless

For 1972 each of the big four among motor makers has announced improved or increased use of recycling technology designed to eliminate overboard oil drainage. In these engines, oil, which normally accumulates in the crankcase of all two-cycle outboards, is now returned under pressure to the combustion chamber. There the excess lubricant is mixed and burned with the incoming fuel charge instead of being discharged overboard. Drainless technology actually was standard on numerous outboard motors as early as mid-1970, but some outboard manufacturers can now state that every model they produce is drainless. Setting an early good example, Outboard Marine Corp., parent company of Johnson and Evinrude, has offered outboard manufacturers anywhere in the world royalty-free use of OMC's patented drain-free technology.

1971 December 1, “Outboard power for 1972. The power race seems to have slowed to a reasonable rumble, and emphasis now is on anti-pollution and anti-corrosion”, in F.M. Paulson, editor, Field and Stream, volume 76, number 8, page 90