Disclaimer: We have no professional or expert qualifications of any kind.
It's fully up to you to check any information you find here with
standard aviation industry sources such as aircraft maintenance
manuals, flying instruction books and, above all, FAA regulations!

Note that there have been three slightly different versions of the Coupe fuel system.  For exact information, post your question on the ercoupe-tech forum (http://groups.yahoo.com/group/ercoupe-tech) and include your model and serial number.

All three Ercoupe fuel system diagrams are included in the Aircoupe Service Manual. (I don't know if the last diagram applies to Forney and Alon aircraft or not.)

If you take a look at where your drain valves screws into the wing tanks, you will see that the nipple that is riveted to the tank, that the drain screws into, goes UP INTO THE TANK.

The nipple is raised about a half an inch above the bottom of the tank. (I hate to say it but its a bad design)

Therefore, just draining the tanks from the valves will not remove all of the water and/or sediment. In order to completely remove all sediment, I would recommend draining the tank then suctioning the area around the nipple at least once a year.

Fred Wellman