Man you cut it close Dave! On my old I/O we had a 52 gallon tank. The problem was the fuel gauge used to fluctuate big time! It would read a quarter tank then close to empty then back to quarter tank. Used to drive me nuts! So we headed to a fuel dock wherever we were on the lake. Filled it up and it took 13 gallons! Wasn't even close to running out! It literally was at quarter tank! My current boat has an analog fuel gauge and a Simrad. So between the two I should be able to figure out how much gas we have left!I'll just throw out there that I've actually put 54 gallons in my 56, so it's probably fairly accurate.