Re: 93' 120hp evinrude on 17' Whaler?
Depends on which 17' Whaler you have. The greatest majority of 16-17' Whalers are rated for 100HP MAX and perform well (38-40 MPH) with 70HP. 100HP will push them to 45-50MPH. 120HP is gross overkill for those lightweight (under 1000#) hulls.
There are a few 17' Outrage models rated for 150HP.
PLEASE believe that the people who rated the hull know exactly what they are doing.
HP rating aside, the transom is rated for 400# MAX. If you decide to go with the Yammy 100F, be sure you don't put over 400#, total, on the transom.
I always got best all-round performance and handling on my 16 and 17 Whalers with 70HP.