Crankcase drainage from 35 outboard motors was measured during normal operation on two lakes in the San Antonio area. The motors included a variety of sizes and brand names, and they were tested under prolonged constant-speed conditions as well as cyclic speed conditions designed to simulate user operation in the field. Four engines of the same group were also tested with a drainage intercepting and recirculating device. Drainage was measured by both mass and volume, and results were also computed in mass per unit time (g/hr) and percentage of fuel consumed by weight and by volume. Analysis of some fuel samples was conducted by gas chromatograph, including a few in which drainage was mixed with fuel by the recirculating device mentioned above. Photographic documentation of the test engines, the drainage systems, and test/measurement techniques was also obtained.

"Contract no. EHS 70-108; program element 1BB038." "December 1974." Report prepared by Southwest Research Institute, Department of Emissions Research, San Antonio, Texas. Includes bibliographical references (pages 65-67).