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Mercruiser Riser elbow gasket question

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  • Mercruiser Riser elbow gasket question

    I am replacing the manifolds and risers/elbows on my 1984 Mercruiser 228 and can't figure out which gaskets to use between the manifolds and riser.

    They sell 3 different. (4 hole, 2 hole and no holes/blocked)

    Mine is full raw water cooled so i assumed I need the one with 4 open slots. The one with 2 open slots seems to be the most common.

    Please help

    Thanks

  • #2
    Re: Mercruiser Riser elbow gasket question

    Have a look at this Merc Service bulletin, it explains which gaskets to use.
    Attached Files
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

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    • #3
      Re: Mercruiser Riser elbow gasket question

      Originally posted by othelloears View Post
      I am replacing the manifolds and risers/elbows on my 1984 Mercruiser 228 and can't figure out which gaskets to use between the manifolds and riser.

      They sell 3 different. (4 hole, 2 hole and no holes/blocked)

      Mine is full raw water cooled so i assumed I need the one with 4 open slots. The one with 2 open slots seems to be the most common.

      Please help

      Thanks
      The correct ones for my 7.4 w/ raw water cooling are the 2 slot ones w/ 2 small holes. Slots go on side to side with the 2 little holes facing fore and aft.

      The 4 slot ones are used when riser blocks are used between manifold and riser elbow. They are to go between the riser block and riser elbow, with the 2 slot ones between the riser block and manifold.

      The no holes ones are used when you have fresh water cooling (and should be used with the S/S block off plates for strength) and go between the risers and manifolds to isolate the raw water from the engine coolant.
      '92 Chaparral 2550 SX Sport
      454 BBC Mercruiser Bravo 1
      Tow with '04 F150 Larriat SuperCab 4x4 5.4 Triton
      US Coast Guard Aux.

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      • #4
        Re: Mercruiser Riser elbow gasket question

        You guys are great thanks

        I have to lok at the boat but in think I need the restrictor 2 slot because I have the connection frm the riser to the termostat.

        Do the slots go fore and aft or the big slots?

        Comment


        • #5
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          Re: Mercruiser Riser elbow gasket question

          Originally posted by othelloears View Post
          You guys are great thanks

          I have to lok at the boat but in think I need the restrictor 2 slot because I have the connection frm the riser to the termostat.

          Do the slots go fore and aft or the big slots?
          The correct ones for my 7.4 w/ raw water cooling are the 2 slot ones w/ 2 small holes. Slots go on side to side with the 2 little holes facing fore and aft.

          '92 Chaparral 2550 SX Sport
          454 BBC Mercruiser Bravo 1
          Tow with '04 F150 Larriat SuperCab 4x4 5.4 Triton
          US Coast Guard Aux.

          Comment

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