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1992 Prostar Ignition Troubles - 351 HO

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  • 1992 Prostar Ignition Troubles - 351 HO

    I am have trouble with my boat. It seems to be somewhat hard to start, but otherwise a smooth idle. Any operation of the boat above idle results it what seems to be a severe miss, almost like it is running out of fuel. I am suspecting ignition problems since I have a brand new 4160 on it.

    I was doing some checking with my meter:

    The boat has factory electronic ignition.
    Primary coil Resistance = 1.9 Ohms
    Secondary Resistance = 14k Ohms
    Keyed voltage to coil = 4.6V

    Shouldn't the input voltage be 12V?? Can I run a temporary wire directly from the battery to the + Coil and see what that does? I am wondering if I have a bad ignition switch or other voltage problem.

    I am a little fuzzy with my understanding of this, not sure if I have a resistor on the coil and if that would cause the low input voltage.

  • #2
    Originally posted by j.robinson389 View Post
    I am have trouble with my boat. It seems to be somewhat hard to start, but otherwise a smooth idle. Any operation of the boat above idle results it what seems to be a severe miss, almost like it is running out of fuel. I am suspecting ignition problems since I have a brand new 4160 on it.

    I was doing some checking with my meter:

    The boat has factory electronic ignition.
    Primary coil Resistance = 1.9 Ohms
    Secondary Resistance = 14k Ohms
    Keyed voltage to coil = 4.6V

    Shouldn't the input voltage be 12V?? Can I run a temporary wire directly from the battery to the + Coil and see what that does? I am wondering if I have a bad ignition switch or other voltage problem.

    I am a little fuzzy with my understanding of this, not sure if I have a resistor on the coil and if that would cause the low input voltage.
    reserved

    93 190
    (safe click)
    John 14:6
    (safe click)

    Comment


    • #3
      After reconfirming my test readings, I have 4.5V at the + side of the coil, but if I separate the ignition wire from the distributor and choke wires, I do have 12V.

      I came across this post, https://teamtalk.mastercraft.com/for...spark-92-ps205

      I Am thinking maybe the Prestolite ignition module is bad.

      Comment


      • #4
        Originally posted by j.robinson389 View Post
        After reconfirming my test readings, I have 4.5V at the + side of the coil, but if I separate the ignition wire from the distributor and choke wires, I do have 12V.

        I came across this post, https://teamtalk.mastercraft.com/for...spark-92-ps205

        I Am thinking maybe the Prestolite ignition module is bad.
        The module can indeed be weak or going farther south. I replaced the OEM in my 93 a while back and noticed a difference. In particular if your module is OEM, I suggest you replace it regardless, to be proactive for better performance. While you are there, add a new cap and rotor. New sprial wound plug wires are recommended.

        I did not read the link but can pretty much sort out the simple 351W systems.

        .
        Click image for larger version  Name:	ei module00.jpg Views:	0 Size:	131.3 KB ID:	2709828

        .
        Click image for larger version  Name:	ei module01.jpg Views:	0 Size:	112.1 KB ID:	2709829
        93 190
        (safe click)
        John 14:6
        (safe click)

        Comment


        • #5
          I would also add one of these coils from Summit Racing. 0.6 ohm epoxy filled Flamethrower II. It will certainly compliment your new module.

          .
          Click image for larger version  Name:	Coil03.jpg Views:	0 Size:	128.8 KB ID:	2709831
          93 190
          (safe click)
          John 14:6
          (safe click)

          Comment


          • #6
            With the modules and coils - its a classic V=IR physics problem. We want the module to generate a very high voltage potential down wire and since those wires don't vary too much our only solution to get higher voltage at similar current is lower resistance.

            But there is no reason for your input voltage to be that low, if you bypassed the ballast resistor you should be near battery voltage at the coil, if you didn't you should be like 9V at the coil which would still run but is not necessary because you won't burn out points.

            Comment


            • #7
              The 92 did not have an OEM resistor that I am aware. Thus the OEM EI and unrestricted voltage.
              93 190
              (safe click)
              John 14:6
              (safe click)

              Comment


              • #8
                Originally posted by waterlogged882 View Post
                The 92 did not have an OEM resistor that I am aware. Thus the OEM EI and unrestricted voltage.
                I didn't think so either - however there have been stranger things. But a voltage of 4.6 is HORRIBLE - and that's the first issue to troubleshoot that should be nearly 14.4 runniing.

                Comment


                • #9
                  Since I'm at the lake now, and getting a new ignition module is not really an option locally. I might just try to throw a new coil at it and see if that makes any difference. What what should the resistance of the coil be for the replacement? The boat does not have a ballast resistor. I was thinking about just going to the local parts store and see if I can match something up. It's possible they have a flamethrower in stock, will I hurt the OEM ignition if I put a flamethrower coil on it?

                  Comment


                  • #10
                    Start w/ your voltage issue, take a pair of jumper cables, run the positive from the battery right up near the engine and then put a jump lead to the coil (this is what hot wiring an ignition means in movies btw) then once you have the coil "hot wired" start the boat, be aware that in this configuration turning off the key will not turn the boat off.

                    Comment


                    • #11
                      Update #2:

                      I was able to locate a coil at a local parts store and replace that, no difference. I'm suspecting it's the ignition module, I just have no way of getting one while I'm here on vacation.

                      I don't know if it makes any difference, but the boat seems to run smooth when revved up under no load. But as soon as you put the boat in gear and start to take off. It has a horrible miss, more like sputter and backfire.

                      I guess the next step is to throw a new Pertronix setup in it. Should I just get the whole new distributor? Or just get the igniter/flame thrower combo to add to my Prestolite distributor?

                      Comment


                      • #12
                        Originally posted by j.robinson389 View Post
                        Update #2:

                        I was able to locate a coil at a local parts store and replace that, no difference. I'm suspecting it's the ignition module, I just have no way of getting one while I'm here on vacation.

                        I don't know if it makes any difference, but the boat seems to run smooth when revved up under no load. But as soon as you put the boat in gear and start to take off. It has a horrible miss, more like sputter and backfire.

                        I guess the next step is to throw a new Pertronix setup in it. Should I just get the whole new distributor? Or just get the igniter/flame thrower combo to add to my Prestolite distributor?
                        Either choice will work. The basis for decision on a new distributor (for me) is two things; 1) are the mechanical advance springs in the Prestolite still fairly good (no rust, intact, and functoning), and 2) is the gear on the end of the Prestolite still good, no wear, and solidly connected to the shaft.

                        My first thought is the EI module at about US $130. The entire distributor is US $300. The new distributor includes the module, etc. Plug and play.

                        I will say this; my input is based on your information and at best, a guess on the most likely subjects to be the issue. No guarantees. Your problem could be any number of things going on. I am offering up suggestions for your assessment and evaluation. I've been married to the 351W for several decades and relate to your issues and frustrations. Where are you located? I can suggest an overnight from Summit but that is a far stretch for me to indulge. Merely a thought.

                        EI module - PNX-91589
                        Coil - PNX-45111
                        Distributor - PNX-D231800

                        If one of these springs is broken, there lies your problem. These springs advance and retard your timing during acceleration. An easy check to see in the basement of the distributor. Leave the plug wires connected, roll back the cap, remove the EI module and have a look. Easy peasy.

                        .
                        Click image for larger version  Name:	distributor springs01rs.jpg Views:	0 Size:	100.7 KB ID:	2709847
                        93 190
                        (safe click)
                        John 14:6
                        (safe click)

                        Comment


                        • #13
                          Originally posted by waterlogged882 View Post

                          Either choice will work. The basis for decision on a new distributor (for me) is two things; 1) are the mechanical advance springs in the Prestolite still fairly good (no rust, intact, and functoning), and 2) is the gear on the end of the Prestolite still good, no wear, and solidly connected to the shaft.

                          My first thought is the EI module at about US $130. The entire distributor is US $300. The new distributor includes the module, etc. Plug and play.

                          I will say this; my input is based on your information and at best, a guess on the most likely subjects to be the issue. No guarantees. Your problem could be any number of things going on. I am offering up suggestions for your assessment and evaluation. I've been married to the 351W for several decades and relate to your issues and frustrations. Where are you located? I can suggest an overnight from Summit but that is a far stretch for me to indulge. Merely a thought.

                          EI module - PNX-91589
                          Coil - PNX-45111
                          Distributor - PNX-D231800

                          If one of these springs is broken, there lies your problem. These springs advance and retard your timing during acceleration. An easy check to see in the basement of the distributor. Leave the plug wires connected, roll back the cap, remove the EI module and have a look. Easy peasy.

                          We are thinking alike, already had the parts in my cart when I read your post. At this point, $250 in parts is less than a trip to the local mechanic. Its a gamble I think I should take. The springs and advance mechanism seems to be in good working order.

                          Comment


                          • #14
                            Originally posted by j.robinson389 View Post


                            We are thinking alike, already had the parts in my cart when I read your post. At this point, $250 in parts is less than a trip to the local mechanic. Its a gamble I think I should take. The springs and advance mechanism seems to be in good working order.
                            Good proactive maintenance, regardless for the 92 year make. Best on the solution.

                            .
                            93 190
                            (safe click)
                            John 14:6
                            (safe click)

                            Comment


                            • #15
                              Originally posted by j.robinson389 View Post
                              After reconfirming my test readings, I have 4.5V at the + side of the coil, but if I separate the ignition wire from the distributor and choke wires, I do have 12V.

                              I came across this post, https://teamtalk.mastercraft.com/for...spark-92-ps205

                              I Am thinking maybe the Prestolite ignition module is bad.
                              That was my post and Waterlogged’s advice is spot on. I’ve since replaced my distributor and I have two replacement modules that will work in your Prestolite distributor for sale in the classifieds.Make me an offer, still sitting on my desk!

                              https://teamtalk.mastercraft.com/for...91589-for-sale

                              Comment

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