I'm averaging about 1.2 litres/nm in slight seas with my 200 Optimax. That's with full fuel (200 litres) and 4 on board, cruising about 33 knots. The Tornado weighs in about 1250kg before the crew board.
Would have thought that about 1 litre/nm would be prefectly achievable with the Yahama F150 on your boat (which I'm sure will be less than 1250kg), with similar loadings and slight seas.
Hope this is of some use - maybe a F150 owner on the forum will be able to give you a more accurate figure.