Just bought a 2008 tracker jon boat with the livewell. its cna take a 15 hp but I have a 4.5 hp mercury. it pushes it actually decently fast, it goes faster then my 10 foot did.

Wondering if decking the front up to the seats from the very front seat to the middle where the livewell with 2x2s and ply wood , carpet would slow me down a lot. also i will be using 2x2s and ply wood to deck between the middle where the live well is to the back seat to match the support beams to make it a level floor.

Simple answer: the more weight you add, the slower you will go.

yeah but how much slower?

I have the exact same boat and did the exact sdame thing with almost the same motor.  I took mine out with my 4 hp once befor modding and it was pretty quick.  It is noticably slower with the weight..I dont have a gps but i know it definatly takes longer to get around know.  Im looking for a 15 hp now.

Check out my project and good luck.

http://www.bassresource.com/bass_fishing_forums/YaBB.pl?num=1214100879/40#40

Joe