Yamaha 25 4 stroke vs Honda 20

[notyme2loose]

I have an Achilles 14 foot inflatable sport boat with a 25 Yamaha 4 stroke which I use as a portable as I travel in my rv. I conidering going down to the Honda 20 which weighs 108lbs vs 141lbs for the Yamaha. I carry this Yamaha around myself so the goal is to ease that and have a smaller unit to store in my 5th wheel. The Yamaha has been great it gets the boat on a plane well even with 4 people in the boat and pulling an adult on a tube. It will run around 28mph with light load(gps). My question is how much would I lose with this Honda 20 displacement drops from 500cc to 350cc. I'm willing to lose top end and pulling tubes with heavy loads as long as I can get the boat up on a plane with my regular load(wife, 3 kids, dog) which the Yamaha can do pulling someone. Any experience or feedback would be greatly appreciated.

[MightyBurn]

I've got the 20 honda on my 16' gheenoe. its a great motor but remember why its so light. its the same block as the 15hp. i can plane no prob. with three people but i loose about 9kts off my top end. i've never tried it with more than three adults but i'm sure it would slow it down considerably. the load your looking to push i think the 25 is the right motor. don't forget yamaha now makes a 20 also.