No announcement yet.

Outboard engine repair - lower unit

  • Filter
  • Time
  • Show
Clear All
new posts

  • Outboard engine repair - lower unit

    This looks like a fun repair, huh?

    It is my buddy's lower unit on a boat he just picked up. The engine has just been rebuilt and purrs like a kitten, but there is some damage to the lower unit that I have been elected by unanimous vote to try and repair.

    Unfortunately, I forgot to take a picture before I started to clean up someone else's FIRST attempt at welding this some time ago (which didn't hold at all). I think the culprit might be the guy below because it looked a whole lot like pigeon $hit!! haha

    Having said that, I might not do much better! I am working with a Millermatic 211 and a Spoolmate. Wish me luck!

    (No doubt, I have a feeling my work will be ground flat and painted.)

  • #2
    I picked up where someone else left off on one of these. They hadn't properly cleaned the material at the joint and was also missing a small piece. I should have cut it off and fit a new solid piece in and shaped as needed after welded. Would have been much easier and quicker in the long run.
    MM200 w/spot controller and Spoolmatic 1
    Syncrowave 180 SD
    Bobcat 225G Plus LPG/NG w/14-pin*
    *Homemade Suitcase Wire Feeder
    *WC-1S & Spoolmatic 1
    PakMaster 100XL
    Marquette "Star Jet" 21-110


    • #3
      I've done a few of those.
      Dynasty 200DX "Blue Lightning"
      Bernard 3500ss water-cooler
      Rockwell vertical mill
      Beverly Shear B-3
      Beverly Shear JR
      Home-made English wheel
      Milwaukee Porta-band
      " Sawz-all
      Tennsmith 36" stomp shear
      Fixer upper 1968 Redface Lincoln sa200
      Powcon 300st


      • #4
        Originally posted by Showdog75 View Post
        That's nice lookin' work!

        Here is my start before I have to shut it down for the night... go the wifey taking me out somewhere to eat for my birthday.

        It's not as pretty as you tig boys, but I think I can piece this back together. The biggest problem will be were the anode goes in place. That is a HUGE hole. There is an aftermarket cavitation (sp?) plate that bolts on, hence the holes. I wonder if I even need to fill in this hole. ?? I probably better. Maybe I'll cut a little jigsaw piece and weld it in place.

        Here is a shot of the first pass. Again, no nearly as pretty as a TIG weld!


        • #5
          I do some of those every summer. For the big holes i just lay it on a piece of clean steel and weld over it, instant patch...Bob
          Bob Wright

          Spool Gun conversion. How To Do It. Below.


          • #6
            what the boat guys appear to do here is put a copper backing strip behind the repair (big hole) and with a spoolgun and preheat, weld to both sides of the crack till its gone then machine the unit to spec.


            • #7
              I've done many of these

              replacement Skegs can be bought. They are of the same grade aluminum as the lower units. Simply cut to match your repair area.

              Here's a link from one supplier:



              • #8
                Originally posted by PA Weldor View Post
                replacement Skegs can be bought. They are of the same grade aluminum as the lower units. Simply cut to match your repair area.

                Here's a link from one supplier:

                that's. Great!
                Nothing welded, Nothing gained

                Miller Dynasty700DX
                3 ea. Miller Dynasty350DX
                Miller Dynasty200DX
                ThermalArc 400 GTSW
                MillerMatic200 with spoolgun
                Lincoln SP-170T
                Linde UCC305 (sold 2011)
                Hypertherm 1250
                Hypertherm 800
                PlasmaCam CNC cutter
                Fadal Toolroom CNC Mill
                SiberHegner CNC Mill
                2 ea. Bridgeport
                LeBlond 15" Lathe
                Haberle 18" Cold Saw
                Doringer 14" Cold Saw
                6 foot x 12 foot Mojave granite


                • #9
                  Your weld is a little grainy which means your material is not very clean, I noticed that You still had a little paint on your preped pc.

                  A grainy weld has contamination in it which makes it weak.

                  Do a little better clean up prior to using filler metal and your weld will be shiny and good.

                  I dont mean to bash you, Just constructive criticism.


                  • #10
                    Outboard engine repair - lower unit

                    Your welding cast aluminum with mig? What are you using for wire?

                    That needs to be tig welded.
                    Miller 350 LX Tigrunner
                    Miller 350P w/XR-Pro
                    Miller 250MP w/30A spool
                    Miller 211 Autoset
                    Hobart Tigwave 250
                    Hobart Beta-Mig 251


                    • #11
                      Thread from January guys, revived by a spammer.