Jim,
I got a new motor. I'm running a 50 hp Suzuki 4 stroke EFI.
I got out a little over 38 miles from the mainland and did plenty of trolling to the north then back to the mainland. If your familiar with San Diego, CA waters, we went from Point Loma to the 181 to the 43 to the 182 and back to Point Loma. Those are offshore high spots. I figure we did about 90 +/-miles total. I have a 14 gallon tank under my console and carried a 5 gallon can of gas for spare. We poured the extra 5 in but probably didnt need it. I never calc'd the exact numbers but I'm getting great gas mileage with this setup- maybe 7mpg??.