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Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

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  • Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

    Sigh... " Sometimes you're the dog, sometimes you're the tree... "

    This time around, I'm the tree.

    Someone gave me this motor and I figured I'd get it running for the kids. It sat for 6 years. I pulled the lower unit off figuring the impeller was shot - it was - along with water in lower unit oil. I checked for leaks - upper oil seals leaking. Pried seals out and tried to get bearing housing off. Wouldn't budge. Worried I'd break it, I brought it to my mercruiser mech. and he acety/oxy torched it and .. he broke it... leaving the broken lower portion cracked ' at home '.

    Now, I have to remove the engine shaft and to do so must remove prop shaft.

    I have no shop manual although getting a SELOC one from library.

    A few questions:

    - Does the lower casing cap need a puller to come off ? Two screwdrivers in the slots ain't doing it. Once I get that off, how hard is it to take the rest apart to get to the bottom of the drive shaft ?

    - What other special tools do I need and what other pitfalls can you help me avoid ?

    - and for Sh*ts & Giggles - how could I have avoided the bearing housing being broken ?

    Lifes a lesson and I keep learning !

    Thx...
    Last edited by YAMAHA1111; August 1st, 2011, 10:35 PM. Reason: my error


  • #2
    Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

    ? Any help ?

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    • #3
      Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

      Uhhhm.. help ?

      Comment



      • #4
        Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

        Hi
        It's difficult!
        I've just removed the bearing housing on my yam 15c (1980s-ish)... And I broke mine too! Fortunately I was able to get it welded free of charge. If it's a similar design and condition it will probably be very difficult to remove.
        The outer rim of the brg hsing is located on the outside of the prop shaft casting. But note, the other end of the bearing housing (the brg hsing is approx 4 inches long overall) is also located - inside of the prop shaft casting. Both were well corroded - a lot of time was spent CAREFULLY heating up the prop casting - on both the outside and inside - with an oxy-acetylene torch and using lots of release gas. On my outboard there are two small cut-outs in the outside edge of the brg hsing - at 180 degrees to each other - I used a hammer and punch against these to persuade it to come off. As soon as I got it to move I used wedges (screwdrivers) in the gap between the brg casing and the prop casting. It takes a lot of time and patiense - and like I said I broke mine too.
        Good luck!
        Rob
        Swansea, South Wales, UK.

        Comment



        • #5
          Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

          Holy Crap ! THANK YOU for a response !

          I figured out a lot on my own - and although bitchy, I was able to get the parts apart without breaking anything. Like you said - heat and a lot of patienet finesse.

          Getting the prop bearing house out was a bear ! I used a lot of Mapp heat and then a pipe wrench. Once it budged a little, I used a penetrating oil and got it to move a little more and so on...

          Now, I have to figure out if the prop shaft and drive shaft wear are within an acceptable amount ( where the oil seals ride )...

          And (2) ultra thin shims 'came from nowhere' before I could see where home was for them. They are paper thin, the same size, but their inside and outside diameters do not give a clear picture of where they belong. My hunch says right above the pinion gear...

          Comment



          • #6
            Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

            I think I'm in the same boat here I've got to remove the lower bearing housing on a Yamaha 9.9d 1992 (i think the same as yours). Is the lower bearing housing threaded so you have to tap it around anti clockwise?

            i have found a Manuel for a later model 1995 that you may be interested in the lower unit seems to be identical on this model but the engine is different, what your looking for about the shims is in section 6 on page 15 https://docs.google.com/fileview?id=...OGFhOWEw&hl=en. the exact measurements could be different in this model so in will need confirming.

            Any tips or hints on getting this out with out damaging in would be great, I'm removing it to replace the oil seal housing because i busted it. what are you using to get the drive shaft out? i don't have the tools and was wondering where i could get them. Also did you have heaps bolt heads turn off I'm thinking that the last person who opened mine up did not know what they were doing and did not add any anti corrosion spray to the bolts.

            thanks for the help iv already got from reading your posts,

            Field

            Comment



            • #7
              Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

              Yamaha1111 / Field
              You're right Field, the drawing of the lower unit is very similar to mine - but there are some differences, e.g. the gear on the bottom of the drive shaft (21) appears to be held on with a nut (20) - on mine it's a circlip: which can be removed by reaching in with a large-ish screwdriver and pushing it off - you may need two pairs of hands for this - also, on mine the shim (23) sits directly on top of this gear.
              The other two thin shims (31 & 38) you will find are located at the back of the forward and reverse gears - they don't look very thin in the drawing!
              The brg hsg is NOT threaded, on mine - but, I tried 'tapping' it back and fore in an attempt to free it up. In fact I hit it quite hard - with very little effect: it did start to turn a little and, in the effort to remove the brg housing, I guess it helped a bit.
              When reassembling make sure to thoroughly coat all threads with an appropriate (thick/waterproof) grease.
              I've not got a manual for mine yet but found a few useful sites providing drawings (for spares) for outboards - just 'google' something like "yamaha lower unit assembly fig 18 ref no2 to 48" and you'll find them.
              Cheers
              Rob

              Comment



              • #8
                Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

                Is the lower bearing housing threaded so you have to tap it around anti clockwise?

                No it's not threaded. It is precisely machined to fit EXACTLY into the lower unit housing. HEAT all around the L.U. housing about 2" from the end of the housing and all around. A lot of heat all around is what you need. I held the lower unit housing in a vise but NOT on the skeg/fin - already snapped that by holding it there ( and had it welded back on for $30 ).

                Honestly, I was at the "F"-IT stage, and held the lower unit in a vise by the bullet shaped gear housing. Then, by using the heat, holding the lower unit housing in the vise - FIRM, I was able to take a big pipe wrench and turn the lower bearing housing just a smidge. It was the first progress I had made at all ! So, I slowly worked it back and forth - sprayed PB Blaster in the seam - let it sit and then heated it again then the wrench. After 5-10 minutes I was able to work the bearing housing quite freely. Then I used those otherwise useless screw-driver tabs to bang the housing off the case... Sigh. Amazing what saltwater does !

                Initially, I busted my upper oil seal housing too trying to remove it. That's why I had to remove the lower bearing housing ( near the prop ), so I could remove the drive shaft. Once you get that lower bearing housing off, take the gears and all out. CAREFULLY remember, draw or take a dig. pix for the re-assembly. Then the drive shaft has a pinion gear at the bottom of it held in place by a nut. I held the shaft in place with a vise grip - away from any important part of the shaft, put a wrench on that nut and turned. Easy off! Then the shaft just slid right up and off. I then had to carefully sawzall the upper bearing busing and housing off as they were fused to the lower unit housing.

                All is now apart and cleaned. I have some wear on an area on the prop shaft ( where the oil seals ride ) and the drive shaft ( where the brass bushing rides ). I need to ascertain if they are re-useable !

                Hope this helps. Be carefull during all this to not marr or ruin any surface on the lower unit housing - ' cause then I think you're COOKED !

                Learning as I go !!!!

                Comment



                • #9
                  Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

                  guys,
                  Thanks for all of the advice I'm going to have a go at this this weekend and see how she turns out. I already learnt a lot doing this job as YAMAHA1111 said learning as i go too. Had to heli coil 4 bolts in the head after the bolt heads turned off , that was not fun and i was going to give up at that point but thought that i could not stuff it up anymore if i had a go one of the replacements looks a bit ugly but ill see if it will hold seal when its done if not ill get a new thread welded. You live and learn i don't know how people work on these things for a living no wonder why they wanted to charge me more than the engine was worth to do the repair (clean out a salt packed engine and change the impeller). If i get it all working again I'm going to convert it to a 15hp just to see if i can. Once again guys Thanks heaps for all the advice ill let you know how i go with it. Where are you guys getting your parts from? They seem to be a good price on here but just wanted to check.

                  Field

                  Comment



                  • #10
                    Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

                    I found the cheapest parts on the web, on sites in the US.
                    But, in the end, decided to get mine locally from a Yam main dealer.
                    Good luck!
                    Rob

                    Comment



                    • #11
                      Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

                      Originally posted by Rob42233 View Post
                      I found the cheapest parts on the web, on sites in the US.
                      But, in the end, decided to get mine locally from a Yam main dealer.
                      Good luck!
                      Rob
                      I could not do that here mate would make the repair uneconomical its going to be a close thing in its self.

                      I had a good go at getting the lower housing out on the weekend, good news i did not break it bad news it did not even move a little bit. I don't think my propane torch puts out enough heat to really make a difference. What do you guys think would be a fair price to have someone else just remove the lower housing $80 bucks or something like that? its all stripped down ready to go. I just don't think iv got the tools to get the job done with out breaking it.

                      Field

                      Comment



                      • #12
                        Re: Yamaha 9.9 1991 Lower unit oil seals / bearing housing ? Aaaah help...

                        I think that the risk of breaking it is almost as great for a qualified mecnanic - that's why many mechs around here don't work on older motors.

                        I used MAPP gas and heated the sh*t out of the housing, 1-2" from the bearing edge - and about 2" wide. Heat it for 5 minutes solid, then get a LARGE pipe wrench around the bearing housing, using the tabs on the housing as leverage points ( have the lower unit held in a vise ) and try to get ANY movement.... THen see my post above - good luck.

                        I'm at a spot where the replacement parts are expensive and my prop and motor shafts are almost un-useable. It would be a be'atch to buy all the stuff I need, put it together and still have an oil seal leak 'cause the shafts are worn....

                        Comment


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