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Mercruiser 888 Lower Unit Replacement MC-1 Pre Alpha 1.47 / 1.5 gear ratio

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  • Mercruiser 888 Lower Unit Replacement MC-1 Pre Alpha 1.47 / 1.5 gear ratio

    I am trying to replace my lower unit per it was stolen when i was servicing it. Does the gear ratio 1.47 / 1.5 affect what unit I buy or can I just by one that fits? Thanks!

  • #2
    Man sorry to hear, hate thieves, low life pieces of @#$%

    If you don't get the same ratio, then at minimum you'll need another prop, but at worst you'll need to find another lower.

    If the ratio is to high like 1.30 or so, you may not be able to find a low enough pitch prop. If its to low like 2.0 you may not be able to pitch up high enough
    94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
    95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
    07 Seadoo GTX
    Merc Adults Only VP Adults Only
    G-Dad always said "First Liar doesn't stand a chance"

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    • #3
      Originally posted by nic420 View Post
      I am trying to replace my lower unit per it was stolen when i was servicing it. Does the gear ratio 1.47 / 1.5 affect what unit I buy or can I just by one that fits? Thanks!
      Ayuh,..... The lower unit, or the whole outdrive,..??

      The gear ratio is in the upper drive, not the lower unit,.....

      The 1.47:1, 'n the 1.50:1 are virtually the same ratio,....
      You can bolt on, 'n run an MC-1, "R", or "MR", or an Alpha 1, up to 1990,.....
      The Alpha Gen.II came out in '91, 'n will Not bolt on,....

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      • #4
        Lower unit was stolen. Still have the upper. What is "R" or "MR"?

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        • #5
          There appears to be slight differences in the stickies, but been wrong many times before

          https://forums.iboats.com/forum/engi...-gen-ii-drives

          Difference in R and MR
          https://forums.iboats.com/forum/engi...the-difference
          94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
          95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
          07 Seadoo GTX
          Merc Adults Only VP Adults Only
          G-Dad always said "First Liar doesn't stand a chance"

          Comment


          • #6
            Originally posted by nic420 View Post
            Lower unit was stolen. Still have the upper. What is "R" or "MR"?
            'R' was the Merc model 1 drive revised, hence, R... 1982. Same gear housing as the MC1, new drive shaft housing.
            'MR' was a major revision, hence 'MR'.. 1984-1985. Same drive shaft (upper) housing, all new gear (lower) housing...
            'Alpha One' 1986-1990. Pretty much identical to an MR....

            Chris....
            xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
            The world takes on a whole new perspective when viewed from 100’ below.
            1972 Bertram ‘Bahia Mar’ 20
            2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
            (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


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            • #7
              You can get a brand new lower from SEI for about $800. Slap it on and you're good to go. The SE 106 lower should fit nicely

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              • #8
                No water pick up at the muff still after re-doing the impeller. Is there a way to check if the hoses from the lower to the upper and transom to motor are clogged?

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                • #9
                  Bought a 1977 boat w/ Mercruiser 888 and Pre-Alpha MR drive.

                  I have redone the impeller 3 times now and every time, the water will not pick up at the muff. I was told maybe the install was wrong, it was not lining up, or something like that from someone on this forum when I did it the 1st time. So I did it again and still no water pick up at the muff.

                  Is there a way to check if the hoses from the lower to the upper, and the transom to the motor are clogged? How do I check if the passage ways ae clogged? Should I remove the hoses to check?

                  Someone also said I might not have it lined up when matting together? Is there a trick to matting the lower and upper together? Please help.

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                  • #10
                    When you have the muffs on the drive without it running, there's a lot of 'overspill' of water. When you fire up the engine, does that overspill diminish? If it does, that means the pump is pulling water in, is there an immediate flow of water from the propeller hub? if yes, then you missed the tube (between the impeller housing and the water pocket cover in the drive shaft housing)...

                    If the water overspill doesn't decrease, then the impeller isn't turning, or there's an air leak in the suction side.

                    Chris.........
                    xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                    The world takes on a whole new perspective when viewed from 100’ below.
                    1972 Bertram ‘Bahia Mar’ 20
                    2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
                    (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


                    Comment


                    • #11
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                      Originally posted by nic420 View Post
                      No water pick up at the muff still after re-doing the impeller. Is there a way to check if the hoses from the lower to the upper and transom to motor are clogged?
                      Ayuh,..... With the lower unit off, back-flush from the t-stat housin', where the hose from the drive attaches,.....

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