Vector Porpoise

I have a 17' 1986 Vector with a 2002 Johnson 115 engine on a Hi Jacker plate and a 24 Raker prop.  It redlines at 5500 with 61.8 speed tops with two adults in it!  The problem that I am having is that it begins to porpoise at about 4000 to 5000 rpms.  Any suggestions?  I have recently raised the engine two more inches, but I haven't been able to try it out yet.

 

Danny: 

Don't be afraid to let this combination rev to 6000 + rpm.  Raising the motor should help this.  Hopefully when you try it out, this has already happened.  Vectors tend to porpoise a lot no matter what you do.  It is just part of the design of the hull.  They run good trimmed down going slow, or flat out trimmed up and not much in between.  Your speed will probably increase by raising the motor.  If you have excessive wheel torque, lower the motor until it goes away.  This would be your ultimate setup. 

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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