Ive checked the Mercury Optimax spec sheet, but cannot find the GPH fuel consumption for a 225 Optimax at 4200 rpm. Can anybody provide information on this?
That's an elusive number as it depends to a large extent on the type of boat the engine is attached to. As a very rough rule of thumb, move the decimal point one position left 225 = 22.5 gal/hr to get (as I said) a very rough estimate of WOT fuel consumption. 4200 RPM is not WOT and as mentioned earlier, it really depends on what type of hull is involved.
