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  1. #1

    Could it be...... the buck

    I posted a little while back about my GPR falling on its face in the chop. Someone mentioned in my thread that it could be the buck!

    Every time I hit a set of rollors and the boat comes unhooked and then rehooks it's like it dies. Just for a second, till the next roller and then it happens again. I never had a chance to get a high speed run in that day. I just got the boat back together a couple of weeks ago.

    Someone mentioned in my thread it could be the buck?!? Well I did a couple of high speed runs the other day and found I think I have the buck. It only did it a couple of times though. Where its real bad is at the end of the run if I let off the throttle the front of the boat slams back into the water and wants to throw me right off the front. I have a triple pipe boat and I haven t GPS it. If I had to guess, somewhere around 75. In my reading it seems pretty rare for the buck at these speeds. I hope this makes sense, and any tips on fixing this would be appricated.

    BTW, I'm running a modded 1200 grate. This boat was set up for CC at one time. I also have R&D tabs and a riva plate not modded.


  2. #2
    Duke's Avatar
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    If the boat has the CC single bar grate and CC pumpshoe its commom for them to dig in when you chop the throttle. Still don't understand what you mean by falling on its face.

    A buck will hit you unexpectedly and lift the back out of the water like you made contact with a log, this then causes the nose to dive and sometimes takes a radical turn to the left or right but doesn't lean into the turn. This uncambered sharp turn can toss you off and usually scares the crap out of you.

    If you are just suddenly loosing rpms its mechanical related and not the buck.

    Hope this helps.

  3. #3
    Ya, this has been the hardest thing to explain. It seems the motor is cutting out, shuts off or looses power when it rehooks. I have the advent box set at 8500 for rev limit. I talked to your buddy Greg and he said to move it to 9000 and them see what happens. That seems scary to me!!! I didnt get a chance to try it yet. It's getting cold here in MI. It just seems when it loads the pump back up from being out of the water the boat shuts off for a split second and then takes off again until it comes unhooked again and the problem happend again.

    The buck sound about right to me. It only did it to me about 4 of 6 passes. Does this sound about right. Can the buck be hit and miss like that. Could you tell is this is the CC shoe if I post some pics of it. I will also get some pics of the sincle bar mod.

    My buck was not bad. Just very slight, but it was still there at around 75mph. The nose never dug in enough to make a nasty turn but I could feel the back end lifting and the front end drop. I also trued my hull a couple years back. Maybe this helped it or hurt it? I havent tried to shim the tabs or the plate yet. Just want to get a better understanding of this.

  4. #4
    Moderator OsideBill's Avatar
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    That hitting the brakes feeling when you let off the throttle is the 1200 grate. At high speeds it can be quite an eye opener when you let off. I had to back off mine slowly to keep this from happening. Change to the 800 grate and this will be less of an issue.

  5. #5
    Soemtimes its real bad!!! I had to do the same, Just ease off the throttle and it didnt do it. Wont I loose quite a bit of "out of the hole" performance with the 800 grate. I will give it a try though. Does anyone have one for sale?

  6. #6
    Duke's Avatar
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    Quote Originally Posted by HCP Designs View Post
    Ya, this has been the hardest thing to explain. It seems the motor is cutting out, shuts off or looses power when it rehooks. I have the advent box set at 8500 for rev limit. I talked to your buddy Greg and he said to move it to 9000 and them see what happens. That seems scary to me!!! I didnt get a chance to try it yet. It's getting cold here in MI. It just seems when it loads the pump back up from being out of the water the boat shuts off for a split second and then takes off again until it comes unhooked again and the problem happend again.

    The buck sound about right to me. It only did it to me about 4 of 6 passes. Does this sound about right. Can the buck be hit and miss like that. Could you tell is this is the CC shoe if I post some pics of it. I will also get some pics of the sincle bar mod.

    My buck was not bad. Just very slight, but it was still there at around 75mph. The nose never dug in enough to make a nasty turn but I could feel the back end lifting and the front end drop. I also trued my hull a couple years back. Maybe this helped it or hurt it? I havent tried to shim the tabs or the plate yet. Just want to get a better understanding of this.

    The motor cuttting out issue has nothing to with the buck other then if its cutting out hard it could be causing the hull to drop simular to chopping the throttle.

    Please post pics of the shoe, grate, plate, pump tunnel, including front and back views to see how all the steps are. An incorrect setup can play havoc on the ski. Maybe we can help.

  7. #7
    The motor cuts out hard! But only for a quick second. It s like hitting a brake for a quick second and the motor shuts down and then takes off again, it all happens real fast. Give me about an hour and I'll have all the pics you need.

  8. #8
    Duke's Avatar
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    Quote Originally Posted by HCP Designs View Post
    The motor cuts out hard! But only for a quick second. It s like hitting a brake for a quick second and the motor shuts down and then takes off again, it all happens real fast. Give me about an hour and I'll have all the pics you need.
    I think your bouncing off the rev limiter. Had to set mine to 8000 something because I kept hitting it on my single that only revs to 7400. This could cause somewhat of an overstuff situation.

  9. #9
    I guess I'll try 9000 like Greg said and see what happens. He reassured me that the motor wont gernade!! That sounds pretty high to me. What curve and limit are most people running with Factory Pipes and the Advent. Greg wasnet much help wiht this, said he's not much of a motor guy. Said I'll have to play with the curves I have 67,44,68,69.

  10. #10
    Here are the pics you wanted Duke. Let me know if you need more.
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