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bent skeg

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  • bent skeg

    hi to all.
    does anyone have any experience on straightening a bent skeg [the lowest section at bottom of g/box] on an outboard motor. [cast aluminium] or any ideas on repairing it
    thanks toby.

  • #2
    On my 40hp Evinrude, I had those plastic "wings" mounted to the anti-cavitation/anti-ventilation plates and I must have hit something because I noticed one of the "wings" was gone one day.

    I dropped the lower unit and took it to a local welding shop and the guy TIGged on a new anti-cav plate for maybe $50 (this was about 15 years ago).

    I believe he packed the gearbox in wet sand before welding to prevent frying the gear oil and seals...

    Edit: If your skeg is just bent, you might want to try annealing it (heat, then quench in cold water) and then bending it back but I have a feeling it'll fatigue/break off, and you'll have to weld on a new one anyway, but it might be worth a try...YMMV
    Last edited by Krunch; 12-14-2008, 08:08 AM.


    • #3
      If it's not bent significantly, leave it as is.

      Alternatively, you can try straightening it by providing a back support (something like a sledge hummer or a wooden mass) and using a dead-blow hammer (or a simple rubber mallet) to gradually eliminate the curve. Don't hit it hard and try to avoid a situation when you'll need to bend it back and forth. I would suggest to use no heat.

      But, again, don't do it unless absolutely necessary. The cast aluminum is quite fragile.


      • #4
        As mentioned, heating aluminum wont help in straightening. If it breaks off when straightening you can either weld it back on or make another one and weld it on in place of the original. Don't let the inter-pass heat get too high or you might just ruin the gearbox. I repaired several on small outboards long ago.
        Two turn tables and a microphone.


        • #5
          This is what I do for a living. I fix dozens a year. On everything from jonboats to 200+ MPH raceboats. I frequent several marinas and several come to my shop as well.
          I try to leave the grease in the unit as it keeps it cooler. If it has the grease removed Mercury recommends re-installing all the bearings and shims and torquing everything back in place with no rubber/paper parts. You can warp the bearing race area if the case is empty/disassembled. If doing it on the boat tilt the unit up and work it like that with the exhaust full of water if it is thru-prop exhaust.
          Heat the skeg (I use a cutting torch) and use a hammer and a backer...if you do NOT heat it... it will bust. You may have to re-heat it several times. Work it slow and keep standing back and re-sighting it as they are usually twisted somewhat as well. Sight it from the front and the back with the prop removed. Almost any aluminum casting that busts has bent before it breaks and straightening it is simply part of fixing it.
          Try to find a hammer with as flat of face as possible so the impressions will not be so pronounced and cause much more time metalfinishing.
          It is much better to straighten the original that cutting and welding on an entire new skeg. There is quite a good bit of extra meat in the radius next to the bullet. I repair many units that have been replaced by who knows who and much prefer to get a v i r g i n unit rather than one somebody has botched.
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