Is it possible to estimate fuel consumption for a Zodiac Pro 4.2 with Evinrude 40hp ETEC, say on an " average " day's holiday use - motoring at 6 knots for couple of hours, maybe at 20 knots for an hour?
My boat seems to run at around .7l per mile. The club boat (5.4 with a 90) at just under 1l / mile loaded.
We worked these out by knowing the distance and fuel used. I think you need to do a run and see what she uses. If you work on 1l/mile then I suspect you'll be fine unless really loaded.