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Thread: new rockhopper installed

  1. #1
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    Default new rockhopper installed

    I installed my new rock hopper on my 20hp honda last night.Took it down river this morning to ty it out,not good.I could not use more than 1/4 throttle or it would over rev and slightly cavitate,must distrupt the flow of water to the propp.I tried all 5 of my tilt/trim settings on my motor,nothing really helped.I had to pull it off down river or I don't think I could have gotten back up.Not really sure what to do now.

  2. #2
    Member mainer_in_ak's Avatar
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    Default

    grit, althoug the rock hopper works great, that is one of the biggest problems with it....cavitation. You might try a slow pitched prop. I make my own custom prop protectors. I use a river runner prop protector, and bolt pieces of uhmw 1/2" poly to it and the anti cav. plate. these pieces are pre formed to take a circular shape. I then drill half in holes all thoughout these pieces........no cav. problems!

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    Mainer,
    Would love to see a photo of what you have come up with.

    George

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    Default Rock gard

    ""'the eng. is to high""", needs to be droped down about 1, 2 or 3 inches , it will go away there is no way to just do it, have to play around a little to get it to stop, an not get it down to much, the best point is when under power it will not cavitate an when you do a power sharp turn it will do it a little that is where you get the best point for your money good luck

    SID

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    Thanks
    kind of a pain,that a guy has to spend money trying new propps or have to figure a way to lower the engine to try to get this to work.Kind of a waste of money I guess,I think I will just take my chances without the hopper installed.
    here are a couple pics

  6. #6
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    Default rock hopper

    the one's I have had built were a little different, the leading edge of the vertical deflector on mine is ""round stock"" an it is right next to the eng not on the front of the plate like yours,as your eng is running very close to the top of the water, an you bar is so far out away from the eng it disrups the water an air gets in, is your vertical bar round of something different ?? I could not tell from your photos , you could move the bar back next to the eng, also the plate on the bottom of the skeg I don't put them on, have had to many problems with them , when going slow over gravel bar it dug up to much gravel for me , don't forget I live in Anchorage so most of the rivers are small can cross most rivers with hip boots an not get water in an not very wide [not counting the pools ]

    SID

  7. #7
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    I have not experienced any problem with the Rock Hopper. I have used one on a 24' freighter with a 20" transom and 25 hp motor and also on a jon boat with a 60 hp outboard. I didn't see any change in speed or fuel efficiency with either rig. They sure saved props!

  8. #8
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    Arrow river runner

    Quote Originally Posted by mainer_in_ak View Post
    grit, althoug the rock hopper works great, that is one of the biggest problems with it....cavitation. You might try a slow pitched prop. I make my own custom prop protectors. I use a river runner prop protector, and bolt pieces of uhmw 1/2" poly to it and the anti cav. plate. these pieces are pre formed to take a circular shape. I then drill half in holes all thoughout these pieces........no cav. problems!
    I use the river runner too, though I did bend my bottom plate on it a week ago - after the weight of the boat was on it I didn't get my weight forward quickly enough... That water was so low this year.

    I'd also love to see pictures of the modifications you did to yours.

  9. #9
    Member mainer_in_ak's Avatar
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    one month folks.....just one more feaking month....and i'll be home! hole yr. away (never again). No pics of my river runner + , but as soon as im back ill post some photos....will prob perform the mod. for who ever is interested.

  10. #10
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    Default

    Rockhopper has great service,

    After figuring out this won't work on my set-up,they are going to refund my money.Talk about great service

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