I got a Merc 150efi on my 20 and it's a mover with a top of 42-3ish on gps

Your fuel tank is easily accessed under the center panel in your cockpit deck. Just a few screws and sealant. Mine is tabbed to the stringers with no foam around it.

Sounds like a 150 would do the trick and there are lots of 20" shaft 150's in my area. I like the EFI Mercs but wouldn't hesitate to hang any of the major brands. Cant wait to get this project rolling.

"Safety First Beat The Hurst"
 

Nice Rig & Happy Grinding. Remember to flip your block's over if it's sitting like that in your yard. No one want's to learn the hard way.

Your friendly Safety Advisor "Wild Bill"

the rudes will work well just depends on what you find

Good eye Wild Bill. Pic is from previous owner, who obviously wasn't safety conscious. I will be using solid hardwood blocks with boat stands and safety chains between. To many kids in my neighborhood to risk an accident.

I ran my both an 18sf and 20ma with a Merc 2.4 225, 2.4 200, 2.4 175 and 2.0 150 . . . never got less than 2.8mpg 4000rpm cruise with a calibrated fuel flow meter. Even at WOT (51mph with the 2.4L 225) I never saw less than 2.0MPG (51 / 22gph = 2.3gph) on any of the rigs.

Propped WOT 5800 a 2.0L 150 doesn't burn more than 16gph . . . It doesn't feed more fuel than that through the stock carbs unless you modify them.

Eggs 2.5L can . . . but that's a different story.

I just checked mine on 2 long trips using the mileage from the GPS vs fuel burned