I have a 2004 Polar cuddy with 2004 F150 ,s. Last year my mileage was roughly 2.5 to 3 mpg running @ 3400 rpm using gas with 10% ethanol and additive. The motors ran fine. In Novemeber 2011 I started buying ethanol free gas and since than my mpg is drastically reduced . As of late, I am averaging 1 mpg using the boat 3 to 4 days per week. Nothing has changed i.e. weight of boat, running speed, etc. etc. . The engines have 1200 hours and regular maintenance is performed, ( oil changes, lower unit, fuel/water seperators, plugs thermostats gas filters. etc. I put a fuel pressure gauge on both engines average around 40 psi. Recently checked plugs after 6 hours of being replaced and each plus was carboned up and black yet the engines run like champs. I have paid mechanics to check things out, computer check and only thing they come up with is engines burning rich. Is there an inherent problem with the 04 models. I few years ago someone mentioned that the omission of oxygen sensors or something like that wa an issue. I need to find an answer because I cannot afford the gas or need to purchase a sail. Any advise appreciated . Again , the only thing that haas changed is that I am using better ethanol free gas.... Thanks Art