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  1. #1
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    Aug 2010
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    Questions about my boats rigging

    Hey, so i have a few questions about the rigging and set up of my boat. I have a 1989 Hydrostream Voodoo, with a 50 hp mercury. the problem is that when getting out of the hole and up onto plane, there is cavitation with the engine, which means the prop isn't getting enough water to it, correct? Also when up on plane they engine has to run at high rpm when the throttle is wide open, so should it be around 6000 rpm when the throttle is wide open? so what my dad and are i wanting to do is make is so it does not cavitate, so can we do this by just switching the prop (we currently have a 19p prop) or if we put a jack plate on the boat in order to allow the motor to sit lower in the water?

    So to sum it up:
    -Should the motor be going at 6000 rpm when throttle is wide open?
    -How can we eliminate cavitation? Different prop or jackplate, or even both?

    Thanks.


    Here are some pictures, They are blurry because i took them in the rain with a go pro. so there is also water spots.Click image for larger version. 

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  2. #2
    Join Date
    Feb 2004
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    North Tonawanda, NY
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    Venting is not all that bad...

    ...and your engine height does not look too high. If the motor vents excessively when taking a "normal" turn at about 3/4 throttle or so then you might want to drop it down some. The prop you have looks like its a stock aluminum prop which will not hook up as well on hole shot as a much more costly SS prop. RPM for that old 50 should be somewhere in the 5500-5800 range, but the older Mercs usually ran just fine at 6000 rpm if underpropped. I'd suggest trying a 21 pitch aluminum, or you can shop around for something in stainless, but they are a bit hard to find for the smaller motors. You could also try having a prop shop add a bit of cup to the trailing edges of the blades- this may help some to drop rpm and may even help the holeshot.
    Doug

  3. #3
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    Thanks for the reply, when the boat is on the railway (like in pictures posted) the hull of the boat blocks the vents on the motor. so like you said to drop it down some, should we try a jack plate? or just see if a different prop will do then if that doesn't change it a whole lot then try the jack plate?
    Thanks,
    Colby

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