I start and taxi on one tank, then change tanks and do run ups and takeoff on the other. I stay on that second tank for 30 mins and switch, then I switch every 60 mins after that.
I have an EI fuel flow meter which flashes a blinking light at me as a reminder every half hour. If I've missed a change and actually need the reminder, I either have a good reason (e.g., unlandable terrain -- do it later) or I chide myself for my lack of discipline.
The actual change: Boost pump on, wait for pressure to increase, switch, count to ten, boost pump off, observe pressure reduce and stabilise. if anything bad happens, I'll switch back and full rich. Hasn't yet.
Andair valve.
I'm intimately aware of how long an aircraft can run on the fuel in the lines and carb bowl. Many years ago, I was in a Glasflugel Libelle, taking the first glider launch after the tow plane had refueled. The tow pilot's routine was to switch the fuel off during shutdown; for some reason he didn't turn it on again for start up.
He had enough fuel in the system to start, taxi from the fuel bunker to my glider, idle while I was being hooked on, and then run at takeoff power for JUST long enough for the glider to become "light" on its wheel... then the engine stopped, and the tug behaved roughly the way a car behaves when the driver jams on the handbrake, while I was 50 metres behind at 30knots with insufficient weight on the wheel for the brake to work.
Somehow I reacted quickly enough to hit full forward stick, full right rudder, and full right aileron while I was pulling the release handle, and initiated a ground loop to avoid ramming the back of the Pawnee. Skidded to a stop sideways about fifty feet starboard of the tow plane, in line with its cockpit.
I think the tow plane ran for over three minutes with the fuel off. Pretty sure I'd have broken both of my legs if my reactions had been just a split second slower.
- mark