High RPM Problem

I bought a used 1989 Bass Tracker 1600 TF with a 115HP Johnson V4 motor. This boat has an inset transom at the bottom.  As I accelerate to WOT the Tach shoots past the 5500 mark almost at 1/2 to 2/3s WOT.  I don't press the issue so I cannot get up on plane.  There is also a porpoising problem. The current prop is a Raker stainless....it only has "Raker" imprinted on the hub so I don't know the pitch.  I believe it is a 13" prop with 3 blades. The motor is mounted on an aluminum wedge plate and has been lowered to the last hole in the motor mount.  To lower the RPMs I have to reduce speed and drop trim creating a rough ploughing ride.  I have not been able to test for rockers yet.  Thought maybe you had some ideas...it seems like I am very under-propped.

Help!

Steve Taylor
Stafford, Virginia

Steve,

Find a prop shop in your area that can 1) tell us what you have for a prop 2) cup and add a little "roll" to the leading edge. If the shop you call is not showing much interest in the project, call the next one. The key to a good prop shop starts with an interested prop man. You have a ventilation problem that should be easy to remedy.

Randy

Please submit whatever questions you have to IHRTechTalk@yahoo.com.  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Thanks,
Mark C.

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