Home Forum Ask A Member Lower Housing Cracked 1957 Big Twin

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  • #939

      Hello All,

      I am completely disappointed. I went out to the garage to do a quick inspection of my 1950’s wood boat, and I noticed the lower housing (right at the seam where the lower housing connects to the housing) was cracked a bit. I unscrewed the oil drain plug, and there was no oil!..Actually the unit and the screw are greasy, so maybe the "guts" inside the lower unit are still covered a bit with oil.. I imagine the last time I ran the boat last season this thing developed a crack, and I just didn’t notice it. I only ran the boat about 4 times last summer, and I had replaced the lower unit oil at that time..It was perfectly fine at that point…maybe a total of 6 hours of the engine running since oil replacement.

      Is it possible that the gears and all that stuff are OK and still able to function? The propeller still turns perfectly by hand, and perhaps I caught it soon enough..I assume it IS possible a little water made its way into the lower unit and it expanded and cracked during one of our recent freezes here in PA.

      Best case scenario: All the mechanics of the lower unit are ok, and all I need is to have a service center inspect everything and replace the lower housing BUT where on earth do I buy a replacement lower housing?

      Worst case scenario: All (or most) of the "guts" in the unit are a disaster, and I need a partial or total replacement, where do I find these parts, and what kind of money (just a rough estimate) am I looking at…


      Completely heartbroken n PA.


        US Member - 2 Years

        Well, it would sure help if you could post some pictures for us to see exactly what happened. For now, you might just want to refill the gearcase with lube to help protect the innards. I know, it will probably just leak out again, but hopefully will leave a nice coating of oil on the parts.
        Finding a outboard shop to work on the old bigtwin might be a little tricky, and expensive. You might be better off finding a good used gearcase assembly.


          Sorry to ask as I’m sure the question is asked a lot. So I have taken some photos and saved them to my Google Drive. How do I post?



            Working to get the pics on here…thanks


                I do have a 1956 35 HP Johnson Seahorse that’s not operable…can I use the lower housing from the Seahorse on the 1957 Evinrude Big Twin? Are they interchangeable?



                  I cannot see the pictures as it just opens a google page for me?

                  If it is cracked where the gearcase meets the exhaust housing, there is no oil there, and that should not be the cause of the no oil. In fact, Im not sure how it would crack there? Unless that was the weak point. Your water drain holes for the gearcase must be clogged, so that the spent cooling water from the last outing stayed in the gearcase, and did not drain, over the winter. OR, there is a seal malfunction.

                  Doing a reseal is not all that tricky. If you feel like it might be beyond you, post a wanted ad in the webvertize here for a good gearcase, it will be MUCH cheaper than taking it to a mechanic to go over. I sell gearcases that I have gone over and resealed with new water pumps for about 100 to 150 bucks or so. Used, as is gearcases ,cheaper. I would think that if you had a dealer go over a gearcase for you, it would run you in the hundreds of dollars all said and done.

                  Next year, always change the oil right before putting it away! That way, you know there is nothing but fresh oil in there. It is always my last step when winterizing.


                    Sorry, my wife is going to help me with the pictures. The crack is on the very top rim of the Lower housing…this lower housing looks like an upside shark fin. The lower housing has flat head screws holding it to the main housing above. The crack is just below the seam where the lower housing (shark fin) and main housing connect.

                    I spoke to Doug at VintageOutboard.com, and he said water had gotten in there and froze causing a stress fracture…the pictures do look like pressure from the inside caused the crack…I’ll try to get pictures for you all.

                    Thanks a million!


                      I just can’t believe I didn’t change the lower unit oil…My Evinrude book says it doesn’t need to be changed but every 100 hours…Unbelievable.

                      None of us can figure out how to get the pictures loaded on here..I will continue to try, and I appreciate everyone’s help!


                        International Member - 2 Years

                        The only thing you have to do is ; create an account on the web

                        upload an image or photo from your computer or the web
                        then copy this , that’s the "Hot Link for Forums"

                        or create something with "photobucket"
                        and copy your photo
                        just try, it worked for me also in the end

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