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    Repower 7.4

    I have a 96 mercruiser 7.4 gen V with a carb.. How easy or hard is it to replace it with a complete 7.4 mpi engine. Is any additional wireing required or will the existing wiring harness still work. Is it worth.the trouble or should I stick with.the same.engine model. Mechanically I can pull and replace the engine I'm just not sure about the fuel system specifics.
    Thanks
    Lee
    Lee
    Albermarle Sound, NC
    1996 Ciera 2855
    7.4 Merc Bravo 3
    MMSI 338223458

    #2
    Where are you getting a complete 7.4 MPI package from? Mercruiser stopped this engine when it’s stock of new engine ran out years ago and replaced it with the 8.1 and 8.2 engines.
    1997 Maxum 2400 SCR 5.7LX Bravo II

    Mike

    Comment


      #3
      It's being pulled from another boat..
      Lee
      Albermarle Sound, NC
      1996 Ciera 2855
      7.4 Merc Bravo 3
      MMSI 338223458

      Comment


        #4
        If it has the 10 pin round connector it will be a simple job to swap.
        1997 Maxum 2400 SCR 5.7LX Bravo II

        Mike

        Comment


          #5
          I know it has a round connector. I'll check tomorrow for the number of pins. My boat is a 96 his is a 98 both 2855
          Lee
          Albermarle Sound, NC
          1996 Ciera 2855
          7.4 Merc Bravo 3
          MMSI 338223458

          Comment


            #6
            Looking at the harness diagrams as long as you get all the harness it will include the 10 pin round connector that interfaces to the helm harness.
            1997 Maxum 2400 SCR 5.7LX Bravo II

            Mike

            Comment


              #7
              So then it will just be an engine swap with maybe some fuel line modification
              Lee
              Albermarle Sound, NC
              1996 Ciera 2855
              7.4 Merc Bravo 3
              MMSI 338223458

              Comment


                #8
                Both engines should run on a Mercruiser cool fuel Gen 2 module.
                Joon, Kathy, Jaden & Tristan
                Uniflite 42 AC, DD 671N
                93 3058 sold
                92 2855 (day boat)
                91 Fourwinns 205 (lake boat)
                Longbranch WA
                Life is Good

                Comment


                  #9
                  Originally posted by Ruffryder View Post
                  Both engines should run on a Mercruiser cool fuel Gen 2 module.
                  OP said his current engine is a 1996 7.4 carb, this would have the mechanical fuel pump on the raw water pump but no cool fuel. The 1998 7.4 MPI replacement engine will have the cool fuel module.
                  1997 Maxum 2400 SCR 5.7LX Bravo II

                  Mike

                  Comment


                    #10
                    I believe you are correct Mike.
                    See I can get it wrong sometimes
                    Joon, Kathy, Jaden & Tristan
                    Uniflite 42 AC, DD 671N
                    93 3058 sold
                    92 2855 (day boat)
                    91 Fourwinns 205 (lake boat)
                    Longbranch WA
                    Life is Good

                    Comment


                    • builderdude
                      builderdude commented
                      Editing a comment
                      You funny guy. Haha

                    #11
                    Originally posted by Ruffryder View Post
                    I believe you are correct Mike.
                    See I can get it wrong sometimes
                    We all make mistakes at some time, recognizing it takes smarts.

                    1997 Maxum 2400 SCR 5.7LX Bravo II

                    Mike

                    Comment


                      #12
                      Since you are pulling the engine from another boat can you also take the entire wiring harness, fuel pump etc. Perhaps even the helm if need be. Is the boat being parted out?
                      Phil, Vicky, Ashleigh & Sydney
                      1998 3055 Ciera
                      (yes, a 1998)
                      Previous boat: 1993 3055
                      Dream boat: 70' Azimut or Astondoa 72
                      Sea Doo XP
                      Sea Doo GTI SE
                      Life is short. Boats are cool.
                      The family that plays together stays together.
                      Vice Commodore: Bellevue Yacht Club

                      Comment


                        #13
                        The boat is not being parted out. So why would I need the helm, is the throttle connector different on the carb vs the mpi? I'm looking to just to drop in the engine, hook up the various connections with as little modification as possible, otherwise I'll just swap out with a long block. I liked the idea getting away from the carb.
                        Lee
                        Albermarle Sound, NC
                        1996 Ciera 2855
                        7.4 Merc Bravo 3
                        MMSI 338223458

                        Comment


                          #14
                          We know you want to make it as simple as possible, and I will say a prayer it goes that way for you.

                          Foot print of the new engine is exactly the same.

                          small modification maybe for the fuel line.

                          What you find when you remove your engine bay wise I don't know, small water intrusion maybe, transom solid etc is anybody's guess.

                          Good time with the drive off to recondition .., clean water passage etc

                          Replacing with up to date hose will be a good idea.

                          i will add one more thing, pressure test your fuel tank. 20 years seems to be where they go.
                          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


                            #15
                            Oh yes, I plan a lot of work in the engine bay when the engine is out. I intend to touch and clean everything, and replace anything that is iffy. Plus drive and bottom maintenance. That's one reason I don't want to send a lot of time converting. Pretty much plan on spending the month of April in drydock.
                            Lee
                            Albermarle Sound, NC
                            1996 Ciera 2855
                            7.4 Merc Bravo 3
                            MMSI 338223458

                            Comment

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