My new purchase has 3 fuel tanks, port and stbd tanks in the engine room and an aux tank in the lazarette. The fuel guages at either helm unit has a toggle for the stbd tank and the port aux. I recently learned the hard way (in that I managed to run the one tank dry and killing both engines) that only one tank in the engine room is guaged, and that the aux tank in the lazarette is measured by toggling the "port aux". Is this typical of Carver 3 tank boats or is it peculiar to the 390 or only on my boat? Does Carver assume that only one tank in the engine room needs to be gauged as both tanks should run down evenly as each engine only draws from and returns to it's own tank? Do any of you with this boat model have a third, seperate gauge for the aux tank or are you setup as I am? None of this was explained to me beforehand so I am stumbling along as I go getting familiar with this boat.