Dan,
Forget the caps with gauges, not worth the money, I had them and traded back for regular caps.
Keep a peice of old hose and when you think your low on fuel insert it down and see how much is left in the tank. That and a flashlight to look in should do it.
Mark,
Why is it there is always 2 gallons of fuel left when the tanks run out? Seems All American and other brands put the suction hoses about an inch to inch and half above the bottom of tank?
Only reason I can come up with is to prevent sucking out the sediment that settles on the bottom, but is that not what the filters are suppose to do?