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Initial timing on a mercruiser 350

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    Initial timing on a mercruiser 350

    I have a mercruiser 5.7L. Engine number 0D385196 in my 1995 2452 ciera classic hardtop. it is listed as a competition ski 1987 - 1995. I need the base timing if someone could share I would be greatfull

    Thanks
    Tony

    #2
    Check online for Mercruiser tuneup specs! There is a lot of info out there!
    Don
    1995 Maxum 2400 SCR LUNA DE MIEL
    1988 Bayliner 2455 (sold)
    1976 Tahiti 16.5 I/O (sold)
    10 ft livingston (lost in fire )
    1987 18ft. Seaswirl cuddy (lost in fire)
    "Is it better to be on a boat thinking about God, or be in church thinking about boating?"

    Comment


      #3
      Is it a Thunderbolt IV or V? If the V do as Don says as a jumper needs to be installed to set base timing.
      1997 Maxum 2400 SCR 5.7LX Bravo II

      Mike

      Comment


        #4
        X2 on what Don77 says. Silly as it seems, the jumper wire is very important. It sets the computer to a base timing mode, then, when operating normally, the computer adjusts that timing for best performance.
        P/C Pete
        Edmonds Yacht Club (Commodore 1993)
        1988 3818 "GLAUBEN”
        Hino EH700 175 Onan MDKD Genset
        1980 Encounter Sunbridge "Misty Blue" (Sold)
        MMSI 367770440
        1972 Chevrolet Nova Frame off Resto-mod in the garage
        Boating on the Salish Sea since 1948

        Comment


          #5
          Hi all!
          Being that the OP states that it is a 95 it is a TB IV, I have a 95 5.7 TB IV and no jumper!
          If it has a competition ski engine I would expect to have had an engine change some time in the past!!
          Don
          1995 Maxum 2400 SCR LUNA DE MIEL
          1988 Bayliner 2455 (sold)
          1976 Tahiti 16.5 I/O (sold)
          10 ft livingston (lost in fire )
          1987 18ft. Seaswirl cuddy (lost in fire)
          "Is it better to be on a boat thinking about God, or be in church thinking about boating?"

          Comment


          • builderdude
            builderdude commented
            Editing a comment
            Boat is a 95 and I'd agree it should be a TB 4 ignition. Maybe op can verify if he comes back to this thread.

          #6
          from what I read here, the OP has a conventional distributor without a computer... if this is the case, this should be what you need to dial it in, providing the harmonic balancer has not slipped and caused the mark to be off...

          this is the information given to me to get my 5.7 running correctly..... which is correct for the NON computerized engine

          For base ignition advance, you will want to see approx 6 to 8 degrees BTDC @ idle speed. (idle speed 550-625)
          You will want to see a progressive advance (in a linear fashion) of up to approx 26 degrees @ 3,200 RPM.
          If the progressive steadily continues with the rpm and then limits itself to 30 degrees or so, it will not be an issue.

          the base timing will have to be where it ends up AFTER the max advance is set correctly. if its too far off to start and idle correctly, then the advance curve is wrong within the distributor and will need to be changed.

          the maximum advance at the correct rpm is the most important spec, as that is the ignition timing necessary for the engine to run under constant load without self destructing.... but again, these numbers and settings mean absolutely nothing at all, if the index mark on the harmonic balancer mark is incorrect... a degree wheel and piston stop could help verify.


          NU LIBERTE'
          Salem, OR

          1989 Bayliner 2556 Convertible
          5.7 OMC Cobra - 15.5x11 prop
          N2K equipped throughout..
          2014 Ram 3500 crew cab, 6.7 Cummins
          2007 M-3705 SLC weekend warrior, 5th wheel
          '04 Polaris Sportsman 700 -- '05 Polaris Sportsman 500 HO
          Heavy Equipment Repair and Specialty Welding

          Comment


            #7
            Thanks for the help. Sorry it has taken me so long to respond. The engine has been changed. It has a thunderbolt IV ignition. It is giving me trouble and I was going to install an ac delco voyager kit. It runs good until it gets hot then I loose rpm until all I have is idle.

            Comment


              #8
              TB IV ignition module controls the advance, base is usually set at 8 btdc. Sounds like a bad coil.
              Dave
              Edmonds, WA
              "THE FIX"
              '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
              (.030 over-Vortec top end-part closed cooled)
              The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
              Misc. projects thread
              https://www.baylinerownersclub.org/f...56-gctid789773

              Comment


                #9
                does the engine mis-fire, cough or sputter, or does it just slowly go down to an idle without any other symptoms?.... ive seen engines do the same when they get hot, but there are other symptoms along with losing power and rpm..... most likely you will find it to be the coil or the ignition module.....

                on an old style points distributor, an internally shorted condensor can cause this also..


                NU LIBERTE'
                Salem, OR

                1989 Bayliner 2556 Convertible
                5.7 OMC Cobra - 15.5x11 prop
                N2K equipped throughout..
                2014 Ram 3500 crew cab, 6.7 Cummins
                2007 M-3705 SLC weekend warrior, 5th wheel
                '04 Polaris Sportsman 700 -- '05 Polaris Sportsman 500 HO
                Heavy Equipment Repair and Specialty Welding

                Comment


                  #10
                  As mentioned by others it’s either the coil but could also be the ignition sensor in the distributor.
                  1997 Maxum 2400 SCR 5.7LX Bravo II

                  Mike

                  Comment


                    #11
                    The test is: disconnect the green/white wire from the distributor. Put a spark plug in top first into the coil center. Ground the outside of the plug. Ignition key on. tap the green wire on a ground. This should cause a bright wire hefty spark on the plug. If it does: sensor, if not, ignition module.

                    A word of advice here. The t-bolt system was designed to work with specially selected components. You MUST use merc's coil. I am an electronic engineer (retired) I tested many OEM car coils including a NASCAR grade coil. They would not work. Also as stated above, marine engines have a grossly different timing scheme (and fuel delivery needs). Some engineer spent many months selecting components to give the performance and reliability needed to make that engine perform well. Unless you are a combustion engineer with a full laboratory at your disposal, don't screw with it. The coils usually, when they go bad starts out as heat related. When it gets hot, they misfire above 2500 RPMs. Cooling them down with water makes them "wake up" then it progresses into misfire at all speeds and then completely dead. The sensor can also be heat related, buts is where you can't get at it. Usually, when it fails, it quits entirely.

                    Now all that said, here's how I would recommend troubleshooting it. Replace in this order, one at a time: Coil, then distributor sensor, them module. Reason: Coil about $75, sensor $100; module $350. Replace in order of reverse cost.

                    Also a word of advice to ALL: when requesting help for a problem, tell us the symptoms and what you did so far. This helps us help you, as we don't chaise our tail....
                    Captharv 2001 2452
                    "When the draft of your boat exceeds the depth of water, you are aground"

                    Comment


                      #12
                      It will loose power. I can chop the throttle and it will smooth out for a little bit then do the same thing until all I can do is idle. I have changed the fuel filter the fuel pump, rebuilt the carburetor changed the coil the module in the dizzy and the dizzy as well. same issue. I can get an after market ignition module for 450 dollars or I can replace the ignition and spend less

                      Comment


                        #13
                        Also I checked for grounding issues. It dose not back fire or run rough it looses power.

                        Comment


                          #14
                          when it starts acting up if I am at mid throttle and I add throttle it will cut out and die if I do not reduce the throttle.

                          Comment


                            #15
                            By the way thanks for the test procedure. I am going to give that a try.

                            Comment

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