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Thread: Nose cone Phenomenon

  1. #1
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    Nose cone Phenomenon

    This week end was unbelievable for Donzi testing for me added a new From Mad dad I believe to be hydro motive nose cone to a 280 drive the boat developed an un believable violent chine walk so bad I could not control the boat. Started about 3500 RPM 45 MPH. Tried pin locations and other props no change. Removed it and back to normal. Also discovered using different props found my torque steer to the left rather than right that it has always been. Both I and Mike are boggled. I have had this boat for 44 years never experienced such lack of control Scary!

  2. #2
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    Yout problem was most likely due to play in your steering and due to the design of that nose cone,it crabs to the side causing the violent chine walk you describe. the only way to correct it is to get all he play out of the steering and make sure nose cone is on straight. I had that exact thing happen to me with my donzi 20 years ago.

  3. #3
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    Why would a nose cone make such a difference saw no performance change with or without all a saw was loss of control. what about reversal of torque steer to opposite side

  4. #4
    mrfixxall Guest

    Fixx

    Quote Originally Posted by Ralph Savarese View Post
    Why would a nose cone make such a difference saw no performance change with or without all a saw was loss of control. what about reversal of torque steer to opposite side

    the torque steer problem was probably from the nose cone not being centered..

  5. #5
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    No it pulled left with solas and ultra and pulled right with my michigan prop

  6. #6
    mrfixxall Guest

    Fixx

    Quote Originally Posted by Ralph Savarese View Post
    No it pulled left with solas and ultra and pulled right with my michigan prop

    I never tried a solas and never will..that prop belongs on a back of a bay- liner cabin cruiser..the blade diameter is to big for a narrow classic..I run a 26 ultra and when approaching 70 mph it does all kinds of wacky things..Hydraulic steering some day

  7. #7
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    Nose cone did the same think to my boat. It was down right dangerous at anything over 35 mph. Unless you have super tight steering or external steering I think that's the nature of the beast. The nose cone adds a lot of surface area in front of the line of pivot. The drive slaps back and forth in the play of the steering kinda like a wobbly wheel on a shopping cart.

    Did you find a prop shaft?


    Frank
    Triple Hatch.
    It's a classic Donzi, not a Donzi Classic.

  8. #8
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    Nose cones can extend the drive forward to a point forward of the pivot point in which the drive is steering around. This will pull the drive around some. As stated, Good steering is the solution.
    Cheers,
    Pismo
    1996 22 Classic
    Red with Stainless Windshield
    Stock Gen VI 502 Magnum MPI-415hp
    Stock Bravo I
    25" Mirage Plus
    74.5mph best @ 5050rpm GPS (Speedo said 80)
    27" Labbed Mirage Plus
    75.5mph best @ 4800rpm GPS (Speedo said 82)

  9. #9
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    my 250 did it too until I went thru and removed all the slop in the steering connections as possible
    including adding a small rubber O-ring in the center helmet bolt.

    after that it was fine
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  10. #10
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    I think nose cones only help a boat over 85mph and are a waste of money on anything slower then that.

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