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7.4 Mercruiser Raw Water Pump with Fuel Pump

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    7.4 Mercruiser Raw Water Pump with Fuel Pump

    I am building a 496 Mercruiser with a Bravo and need to know if I can use a block mounted fuel pump? I want to eliminated the pump mounted to the belt driven raw water pump. I assume the reason for that was to use a mechanical pump on Gen V and VI big blocks that were not provisioned for a block mounted pump. My new engine is a MkIV and has the pad. I do not like the idea of such a small cavity for oil to lubricate the pump arm. Besides, the raw water mounted pumps are costly.
    1990 Four Winns 200 Horizon 5.7 OMC(sold)
    1989 Bayliner 2775 Ciera building 496 and Bravo 1 Mercruiser.

    #2
    Electric fuel pump would be the way to go.

    In my inexpert opinion.
    Be good, be happy, for tomorrow is promised to no man !

    1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

    '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

    Manalapan N.J

    Comment


      #3
      I agree with Chief on this. Not only would you need to open pad and tap holes to mount the pump I don’t think 5he new design has the eccentric that the pumps arm needs to ride on. The design you have has been around since 5ge mid 90s and works well as long as it’s maintained however maintance of 5e raw water pump is a PIA. Going to an electric pump is easy to do.
      1997 Maxum 2400 SCR 5.7LX Bravo II

      Mike

      Comment


        #4
        May i also add, i would go with a crank mounted raw pump.

        Wasn't asked but just sayin ... if this were my engine, that's what i would do.
        Last edited by Chief_Alen; 11-18-2017, 08:37 AM.
        Be good, be happy, for tomorrow is promised to no man !

        1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

        '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

        Manalapan N.J

        Comment


          #5
          Read the first post completely, he is building a Mark IV...........it has a mechanical fuel pump provision.
          Yes, you can do a mechanical pump and in the end would be the most cost effective. No oil pump switch interlock / safety etc..
          " WET EVER "
          1989 2459 TROPHY OFFSHORE 5.8L COBRA / SX
          mmsi 338108404
          mmsi 338124956
          "I started with nothing and still have most of it left"

          Comment


            #6
            Originally posted by dktool View Post
            Read the first post completely, he is building a Mark IV...........it has a mechanical fuel pump provision.
            Yes, you can do a mechanical pump and in the end would be the most cost effective. No oil pump switch interlock / safety etc..
            Yes, I have a custom ground hydraulic roller cam and it has the pump lobe. I should be good to go.

            1990 Four Winns 200 Horizon 5.7 OMC(sold)
            1989 Bayliner 2775 Ciera building 496 and Bravo 1 Mercruiser.

            Comment


              #7
              Your carb will also need to have a "ruptured diaphragm drain inlet" on it if not already equipped with one.
              " WET EVER "
              1989 2459 TROPHY OFFSHORE 5.8L COBRA / SX
              mmsi 338108404
              mmsi 338124956
              "I started with nothing and still have most of it left"

              Comment


                #8
                Originally posted by dktool View Post
                Your carb will also need to have a "ruptured diaphragm drain inlet" on it if not already equipped with one.
                I will be using a marine mechanical pump with the proper vent to the carb
                Last edited by Helibob; 11-21-2017, 07:44 PM. Reason: Misunderstood question
                1990 Four Winns 200 Horizon 5.7 OMC(sold)
                1989 Bayliner 2775 Ciera building 496 and Bravo 1 Mercruiser.

                Comment

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