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mark 30h and mark55h lower unite bearings

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  • mark 30h and mark55h lower unite bearings

    i am rebuilding some mark 30h and 55h lower units. does anyone have the pinion bearing and prop shaft bearing numbers? not the mercury part number but the ones on the bearings. also the manufacture name. the units are going on some quincy looper restorations.

    frank novotny


  • #2
    Call Alan or David VanWeele at aeroliner-boats.com... they have all the parts.

    Dean F. Hobart


    • #3
      Here you go: The needle bearings inside of the MK55H are Koyo GB1112. (Not B1112!). The drive shaft ball bearing is Fafnir S8K.
      The prop shaft ball bearing is Fafnir 9105K. The needle bearings in the tail cone are either B118 or B1112 by Koyo.

      The front needle bearing for the top shaft in the MK30H unit is GB98 by Koyo, the drive shaft needle is GB912 by Koyo. The drive shaft ball bearing is S7k by Fafnir, the prop shaft ball bearing is 9105K by Fafnir. The tail cone needle bearings are GB98 by Koyo.

      Have fun with your project.



      • fbref5269
        fbref5269 commented
        Editing a comment
        thank you. are they all still available

      • larry herman
        larry herman commented
        Editing a comment
        Who would be the best company for most bearings, seals and needles these days ?
        Detroit Ball Bearing Co. was the place at one time till Detroit died, typ dem city.