Evo Engine on Airboat

Discussion in 'Engine, Fuel and Exhaust' started by chuckitt, Sep 20, 2008.

  1. chuckitt

    chuckitt Member

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    Hello, I'm new to the site and this is my first post. I built an airboat with the
    Evolution engine for power. My problem is the vibration. Can this engine be
    tuned to eliminate most of the vibration? I installed a fluid balancer on the
    crank at the 3 inch sproket and it helped some. We are using the HI-4 ign.
    I tried to post some pictures in the gallery and failed. I will try again.
    Thanks, Chuck
     

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  2. glider

    glider Veteran Member

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    Kind of hard to tune the vibes out on 4" pistons. It looks as if you have some mounts to isolate the vibes but a full cushion mount like those found in cars may help but would have to be fabricated.

    A ONE bladed prop??? Talk about vibrations :D
     
  3. chuckitt

    chuckitt Member

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    Thanks glider. That picture was taken before we had all the blades put on. The rubber
    mounts are hard rubber that we use on big engines. I plan putting some soft ones on tomorrow
    and weld in some gussets on the mount plates. I have built airboats with engines from
    the 35 HP briggs up to the 572 big block chevy. We just haven't had an engine shake
    this much and thought someone might have tuned one or done something to eliminate
    most of the shake. Thanks, Chuck
     
  4. Flashback

    Flashback Active Member

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    it's a harley = it vibrates the hell out of everything the only reason you dont feel it on the newer dressers is the rubber isolation mounts they use the engines still vibrate...

    on another note harleys belong in bike frames it's just wrong on so many lvl's lol
     
  5. chuckitt

    chuckitt Member

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    I put a VW on a rubber raft an drove it in the rapids at Kernville Ca. when I
    was on Junk Yard Wars. Now we are building the mini airboats using the Briggs
    35 HP and the Kohler 40 HP and making them run on dry ground. They are
    V-Twins and they are the hottest selling airboat today. We have many
    customers that own Harley's and some of them said if we make the EVOPRO
    work, they will buy one. The EVOPRO just took first place in the FAA Airboat
    Show at Wildwood FL.. I just thought there might be a guru on this sight that
    had done something to eliminate most of the shake. We have put a fluid
    balancer on the crank and changed the prop to a heavy wooden prop. Today
    we are going to change the motor mount rubbers to soft rubbers and install
    a fluid balancer on the prop shaft and see if that helps. I thought there might
    be something we could do with the tuning of the engine to help.
    We have video's on Youtube.com that show our mini airboats running. To
    see them, in the search, type in mini airboat. If they perform that good with
    40 HP, how good would it do with the 80 HP EVO?
     

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  6. glider

    glider Veteran Member

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    You may consider the TC88 B motor with the balancers in it like from a softail. They shake just a bit but nothing compared to the evo.
     
  7. chuckitt

    chuckitt Member

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    Thanks glider, I will check the specs on it if i can't make the EVO work.
    Chuck

    Here are new pictures as of this morning. Chuck
     

    Attached Files:

    Last edited by a moderator: Sep 21, 2008
  8. glider

    glider Veteran Member

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    Ever try those blue vibration idolaters on top of the mount stud also with a large area washer to kill some vibes? With the lock nuts on there it should help but as it is the vibrations are being transmitted with the washer on top through the stud and into the boat.

    Looks like you finally added another blade to the prop. :D
     
  9. chuckitt

    chuckitt Member

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    Yeah glider, we have the rubbers on the bottom of the bolt also. I have some soft
    black rubbers i'm putting on now. I just noticed the pipe on the # one cylinder is running
    lean. I have to learn how to set up the FireBall HI-4 single fire ignition that we installed
    of would the stock ign be better?
    Thanks, Chuck
     
  10. glider

    glider Veteran Member

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    Nothing wrong with the stock ignition on the evo.

    What I meant is an isolator on top and bottom of the engine case on the stud, like directly below the locknut