Is Yamaha 115 4 stroke enough power for a 73 Seafari ?

[Terry England]

Originally Posted by coltblue69

Forgot to mention that it is a 73 20 ft Seafari

If you get either Gillie or Ken Reeves (PropGods) to dial your wheel in I believe you would see something like -
Minimum planing speed - 15 Mph
Cruise Speed - 20-24 Mph
WOT - 33-35 Mph
You'll probably be well north of 3 mpg.
If that would be suitable for your use, you will be happy with that motor. Have it serviced regularly and it will treat you right.