Angier,
I have an A36 Bonanza with Osborne Tip Tanks.  They utilize a transfer pump and a switch mechanism that senses pressure (I think). The switch turns itself off when the tip tank runs dry.  To start the transfer you must turn the momentary switch to "on" and hold it there for about 5 seconds.  Once pressure builds, then the pump continues to run until the tank is dry.  May be something to check out.
Craig Berland
IV-P N7VG

Yesterday's flight from KBVY to KEFK on the Canadian border and back provided a good opportunity to experience lean of peak performance for the first time. About 80º lean of peak is where roughness became noticeable. With fuel flows jumping around due to ongoing electrical issue(probable), it's not at all certain what the correct flow rate was but it was bouncing around in the 6-9gal range at 8500ft. Several weeks ago I installed an LED indicator in the panel to let me know when the auto fuel system relay was energized since I wanted to be absolutely sure fuel wasn't being pumped overboard at the high level, it wasn't. This flight was also the first time I ran the wing tanks dry. Since I could not hear the transfer pumps in normal operation, I was hoping to hear them when running dry but I could not. I'm thinking that an optical sensor in each fuel transfer line might be useful to know for sure the tanks are empty so the auto transfer system can be deactivated so as to not have the pumps running dry.

Angier Ames
N4ZQ
25hrs and beyond Phase I