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  1. #1
    Bullet/Reels4Sale/Rods4Sale Moderator jayfaro's Avatar
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    Mar 2007
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    Townsend, MA
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    3,876

    2018 300 Sportmaster lower gear lube

    2018 300xs Sportmaster
    #1E053915
    Hey guys
    I pulled my prop to check out the gear lube and it’s milky. With the winter coming I drained the gear lube and bought the Merc Hi Perf gear lube and the pump. It took all 32oz and didn’t come out the top vent hole. I did an internet search on the gear lube capacity on the SM and I found a bunch of different answers ranging from 26-32oz.

    I can’t remember how long ago but do remember seeing something from Don about this but can’t find it. I thought it had to do with adding 32oz and then draining a couple ounces out once it started to come out the top.

    Anyway, I’ll be bringing it for seals in the spring and won’t be used again this year.

    Jay

    Also where can I buy the upper vent screw and lower fill screw along with seals or just the seals?
    Jay Faro
    Bullet 21xdc/300xs

  2. Member crank68's Avatar
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    Mar 2011
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    Kenly, NC
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    17,416
    #2
    Different amounts depending on how the case is shimmed...fill it till it runs out then drain a couple ounces. From what I’ve seen a SM case doesn’t vent particularly well so some “milkiness” is kinda normal. I personally change mine 2 times per year.
    BULLET 20 XRD/250 Merc Sport XS
    www.ncboatguy.com

  3. Member
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    Jul 2015
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    Leander tx
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    675
    #3
    I always put 28oz in mine it’s better to have it a little low for expansion especially if you make long hard runs. The shift shaft seals like to push out from expansion. Something else to consider is the mad efi shift shaft seal carrier and driveshaft seal carrier it doubles up the seals
    Last edited by Kyle08; 12-01-2020 at 06:48 PM.
    Bullet 21xrd Mercury 300xs

  4. Member
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    Nov 2008
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    Raleigh NC / Falls Lake
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    #4
    Any Mercury dealer or Boats net will have them .

  5. Member
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    Nov 2008
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    Raleigh NC / Falls Lake
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    #5
    Quote Originally Posted by crank68 View Post
    Different amounts depending on how the case is shimmed...fill it till it runs out then drain a couple ounces. From what I’ve seen a SM case doesn’t vent particularly well so some “milkiness” is kinda normal. I personally change mine 2 times per year.
    +1

  6. Member
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    Jul 2012
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    Maumelle, AR.
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    #6
    I can't remember how much I put in my 2016 Jay, Seems like it was more than one jug

  7. Member
    Join Date
    Oct 2015
    Location
    Ohio
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    3,297
    #7
    Could be the shift shaft seal as those are prone to fail and leak. I would go ahead and drop the lower and change those seals. Pretty easy job just buy the kit. When you refill lower put in enough so that the fluid leaks from the top vent hole. Plug the top hole and remove the pump and drain 1 to 2 ounces of the fluid. Plug the holes and you are good.
    2014 Bullet 21xrs
    2016 Merc Opti 300hp Serial #1E053115