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Difficulty removing lower end from Yamaha 15 Enduro

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  • Difficulty removing lower end from Yamaha 15 Enduro

    I am having difficulty removing the lower unit from my 2006 15hp Enduro 15DMH. I have done this on older Yamaha's and some Merc's and have never had such a hard time. I have removed the 4 bolts securing the lower unit to the leg and have loosened the shift linkage. The lower end drops about 1/16" and stops. You can wiggle it a bit so I'm sure its not the dowels holding it. Normally the lower unit takes a bit of pulling and then the drive shaft slides out of the power head. I have tried shifting through the gears as well as turning the engine over in neutral and in gear. Sounds(feels) like some thing is hanging it up inside the power head.

  • #2
    Are you sure there's not a 5th bolt under that zinc trim tab?....


    • #3
      two things.
      one is the drive shaft is hung in the lower crank seal carrier or the drive shaft splines have stuck in the crank.


      • #4
        I will look under the zink tomorrow but that would have to be an awfully long bolt.
        If the drive shaft is hung in the power head what should I do, keep pulling?


        • #5
          that seal carrier has a long tube.
          about 3.5"
          its ID is tapered smaller at the shaft entrance.
          occasionally corrosion builds up and makes shaft withdrawal difficult.
          I have seen them swell so tight it locks up the power head.


          • #6
            I had no idea the driveshaft could be locked to the crankshaft this way



            • #7
              its why I always ask.
              how often should a well maintained outboard need a water pump.

              its a simple answer.


              • #8
                Originally posted by almetelo View Post
                I had no idea the driveshaft could be locked to the crankshaft this way

                This is why I won't let a mechanic touch my motor if there is any way at all that I can avoid it.

                One, they apparently don't add a dab of grease on the drive shaft splines (but then Yamaha does not bother to add grease to the drive shaft support bushing either so maybe the mechanics are following Yams lead).

                Then they beat the hell out of the motor getting it apart. Oh well.


                • #9
                  I have no clue if is a better (I mean gentle) way to take apart the LU.

                  What worried me was my impression that the mechanic just seems didnīt prevent the fall on the LU on floor (luckily didnīt happen) which could damage the LU, sked, prop etc

                  On video description say minor damage (fortunately)


                  • #10
                    I guess that it would have been too difficult to have a helper hold the lower unit when it broke free.

                    I was thinking of not only damage to the lower unit itself but also to the drive shaft that appeared to be bending.

                    Why in the hell did he not remove the propeller in the first place???


                    • #11
                      I've never encountered seized spline in large engines, only a stripped spline.....


                      • #12
                        Now I've seen the video and learned (how to do it and how not to do it)

                        If alone I would use some type of bench/table under the LU and 2 pieces of wood boards between the chisel to avoid more damage on LU and mid section


                        • #13
                          I'm not in the business but I was not expecting seized driveshaft splines on a recent motor...


                          • #14
                            I cant believe so many people did not think, or have never come across the drive shaft getting stuck in the crank, plenty have had to be cut to remove the lower unit, and then the power head removed to get the spline part of the drive shaft out.


                            • #15
                              Stuff that mechanics may see or know about will never be seen or known by the average boater.

                              Stuff that Yamaha may see or know about will never be seen or known by the average mechanic. Or the most experience mechanic(s) for that matter.

                              I retired from the aerospace industry. Many that worked there were reluctant to ever get on an airplane. Those in the industry saw and dealt with stuff that the average passenger could not in his wildest imagination have dreamed about.

                              This is like Chinese food or sausage. Very tasty. But, it is not a good idea to see it being made. Some things are better left unknown.