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  1. #1

    Pump pressure relief valve.

    4 stroke newbie dork question. What - how - why are these trending on 90 mph plus boats.


  2. #2
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    long story short when you end up going faster (mph), more water fills the pump tunnel then the prop can process which leads to what they call a "buck" or basically that water trying to go into the pump tunnel gets compressed and cant go anywhere which pushes the ass end of the ski up and out of the water driving the nose down, sometimes with serious consequences. the pressure relief basically let the water out of the tunnel area (bleeds off pressure) before all that bad stuff happens

    you can think of it like trying to hold a fire hose flat against the pavement full blast, its going to push you back hard, same thing the rear of the ski does

  3. #3

  4. #4
    Great info! Just who figured that out?

  5. #5
    What speed is point when necessary?

  6. #6
    YAMAHA POWAAAA !!!!! 1_Fast_SHO's Avatar
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    Quote Originally Posted by Seadoodoc View Post
    What speed is point when necessary?
    i got some for sale

  7. #7
    mibunkerking's Avatar
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    Quote Originally Posted by Seadoodoc View Post
    What speed is point when necessary?
    different hulls stuff at different speeds. the 08 rxpx's stuff just above 80, the newer rxpx T3 hull stuffs around 90. some of the yamaha's where stuffing below 70 in stock form.

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