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!

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.

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

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Originally Posted by Ralph Savarese

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

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

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

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Originally Posted by Ralph Savarese

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

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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 :)

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

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.

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

I think nose cones only help a boat over 85mph and are a waste of money on anything slower then that.