[Fr. Frank]

I have a 23' Tsunami, '88 225 Johnson w/new powerhead. I cruise at 4200 rpm, 28 statute mph, at 1.9 - 2.0 mpg calculated.

My 20' Seafari, '91 150 Merc, reman'd in '02, cruises at 4300 rpm, 35 statute mph, 9.9 to 11.0 gph on the Navman 2100, or 3.2 - 3.5 mpg depending on sea conditions and air temp/humidity.

Now Wide Open Throttle produces 51 statute mph at 6150 rpm, burning 18.8 - 19.4 gph, or 2.6 - 2.7 mpg.

Here's the mindblower: If I drop back to 3500 rpms (minimum planing speed in a chop), my speed falls all the way back to 23 mph, but fuel flow is 9.6 gph, or 2.4 mpg. I get better fuel economy at WOT than at 3600 rpms, largely, I believe, because of the greatly reduced wetted surface.

But a friend in Juno Beach, Larry, has a '74 Seafari w/ 1994 Mercruiser 140hp. He burns 7.75 - 8.0 gph turning 3800 rpm at 34 mph, or 4.25 to 4.4 mpg.

What kind of mileage are you guys with 4S outboards getting?