Outboard MPH question ??

20 on a good day would be my guess.

20 mph would be a good start with you in the boat then the more people and equipment the slower it will goes

To compute the theoretical maximum speed of any boat, multiply the top RPM of the motor and the gear ratio to get the actual number of RPM's at the prop and then multiply that RPM figure by the pitch of the prop.
 
This maximum speed is just that, the maximum, it presumes that the boat has no drag on the water and that the prop has no cavitation, as if it were going through a solid, like wood, and not water.  This maximum can never be achieved, so your actual speed will be something less.
 
Using this calculation will turn a lot of 70 MPH boats into 55 MPH boats in about the same fashion as a scale will turn 10 pound fish into 6 pound fish.

Here's an online version of DarDys post.  Good info.

http://www.rbbi.com/folders/prop/propcalc.htm

put a 60 on it and change the stickers

ORIGINAL: bluntman

put a 60 on it and change the stickers

I have no problem with a 20 on it for LA or Pymy. That will be the largest lakes it will be used on. On the upper Allegheny we run a 18' Tracker with an inboard 120hp jet. It tops out at about 40 mph. Speed really isn't all that important to me but it has to be reasonable. Thats why I asked what I could expect. Thanks for all the replies.