How many gallons does my gas tank hold?

Question

How big is the gas tank in my 2004 Four Winns Freedom I/O sterndrive with a 190 hp 4.3L Mercruiser?

Answer 1

Other than checking your owner's manual, or running out of fuel and refilling, you could measure the outside of the tank (L-W-H) and find how many cubic feet it is.   Google an online conversion to find out how many gallons it equals.  Then (this is important, eh) DEDUCT say, 10 gallons from the result, cuz you measured the outside of the tank, not inside where the fuel is.  Also most tanks will not draw out the last couple gallons.

Answer 2

20?

Answer 3

drive it until empty, then fill it up