I'm looking at buying a 2000 model Mercury 300 promax. I currently have an 01 225efi mercury on my boat and on average use a quarter of a tank of gas fishing. I know the 300 is gonna be bad on gas but was wondering how much worse. I'm wanting to get a bigger motor to push my 21'10" bullet faster. The promax has about 250 hours on it and 120# of compression across the board any ideas about what they sell for? I don't know anything about these motors other than their supposed to be fast and just wanted to ask some questions to make sure I wasn't getting something I'd regret.