Ok, now I have a “copy” of the owners manual. Thank you again WB and other responders. I now realize that my gasoline cap does NOT have a VENT-Screw. Perhaps this is NOT the original gas cap thought it does appear to be vintage and it fits perfectly. I presume that without the vent screw open (as instructed in the operation manual) the motor will quit on me once it is going because a vacuum will be created in the gas tank as gas in burned during operation…is this true? If yes, does anyone have a extra gas cap for a Bendix Eclipse TMD 1939 for sale ??? 😉