Unexpected shut down

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  • julienrobi3
    Senior Member
    • Feb 2021
    • 13

    Unexpected shut down

    Hello!
    I had a weird experience with my atomic 4 today. We were arriving at a marina so we turned on the motor to lower the sails. After a few minutes, the motor shut down unexpectedly. We tried to turn it on again, unsuccessfully. Hopefully, another sailboat was there to carry us to a dock where we could try to figure out what was happening.
    So, after some tests, we figure out we had sparks, and we had fuel going in the carburetor. But we thought that there wasn’t fuel going into the cylinder (without being completely sure). So our conclusion was that the carburetor was maybe plugged somehow, and that I had to clean it.
    But a few hours later, without doing having done anything (except drinking a few beers to forget our misfortune), I tried to turn the motor on again, and it did! Everything is going great now. So I’m even more confused. How could the motor not work in the afternoon, but later on did?
    Thanks again for your help everyone!
  • Dave Neptune
    Afourian MVP, Professor Emeritus
    • Jan 2007
    • 5046

    #2
    Oh it can shut down and restart later for a couple of reasons. A little more info on the "way" it shut down would help. If it shut down like you turned it off it is probably electrical like a coil or a bad connection somewhere. These old boats were put together with a wiring harness for the engine and have a "trailer style plug" that is known to be an problem. It could be a bad key switch too.
    Next time it shuts down be ready to check for spark and voltage to the coil when it happens, not later.

    Do you have points or an EI? Also do you have a std or electric fuel pump?

    If the engine sort of stumbled when quitting it could be a fuel problem usually with an electric pump.

    Dave Neptune

    Comment

    • julienrobi3
      Senior Member
      • Feb 2021
      • 13

      #3
      Hello!
      We were going at really low regime, and we just thought it had died since we were at too low regime. We didn't hear anything different from when we usually turn it off.
      We have points. But right after it died, I've checked for sparks on one spark plug and it did spark. So could it really be a problem with the ignition?
      And we have an electric fuel pump that I've installed this spring. To know if it worked, we disconnected the pump from the carburetor and turn the ignition on, and gas was pumping alright.
      We thought it might have been the carburetor because when we unscrewed one of the spark plug and tried to start the engine, we couldn't feel any gas going in the chamber. (Is this the best way to test this?)
      But then again, it started to work again a few hours later, so I'm not sure anymore.

      Comment

      • Dave Neptune
        Afourian MVP, Professor Emeritus
        • Jan 2007
        • 5046

        #4
        What do you mean by you couldn't feel any gas going into the chamber? Do you possibly mean compression?
        When you installed the electric pump did you install it with an OPSS (oil pressure sensing switch)?

        Dave Neptune

        Comment

        • julienrobi3
          Senior Member
          • Feb 2021
          • 13

          #5
          I meant the combustion chambers. I took off one of the spark plugs on top of one combustion chamber and while starting the motor, tried to feel with my hand if there was any gas spilling out (I'm not sure if it was safe or not, but apparently it was the way to check if there was gas going in the combustion chamber).
          I have an opss, but for troubleshooting I bypassed it, so it wasn't the problem.
          Is it possible that water went in the carburetor and created the problem? So when I tried again a few hours later the water sank in my water separator and wasnt a problem anymore?
          Because today, the motor runs perfectly, but I'm still a little bit anxious that the same problem happens again!
          Thanks again for your help!

          Comment

          • ndutton
            Afourian MVP
            • May 2009
            • 9601

            #6
            So far your tests point to an internal carburetor problem but aren't quite rock solid conclusive. Another useful test (in combination with the others) that could nail it down is starting fluid sprayed into the carburetor throat at the time of shutdown.

            This could be something as simple as a stuck float valve, released in the subsequent hour by the boat's motion. I think it's reasonable to rebuild the carburetor at this time. How long since the last rebuild? There is no downside.

            Hint: rebuilding and thorough cleaning are the same work.
            Neil
            1977 Catalina 30
            San Pedro, California
            prior boats 1987 Westsail 32, 1970 Catalina 22
            Had my hands in a few others

            Comment

            • Theo Lewis
              Senior Member
              • Jan 2021
              • 12

              #7
              Path forward

              Greetings. I’m following this one as I am in exactly the same circumstance. Interested in hearing advice or suggestions for a list of things to investigate/service in order to resolve. Suspect I angered the elves by mentioning in a recent post that my engine had been running well. My fuel system is new from the tank cutoff valve to the intake manifold as of last year. Fuel lines, Racor, Facet with OPSS, polishing filter, new carb, new linkage. 50hrs on all. Engine has points and is due for a tune-up. I haven’t changed plugs or performed a tune up since purchased 3 years ago as it has been recently, and is again, running smoothly. Idle was set at about 900, after this incident it idles a little lower, just above 800. Engine runs normally about 150 when warmed up, 155-160 under load, oil pressure is around 45 psi when cold, drops to about 40 once warm, occasionally down to as low as 30. Two weekends back I filled up at the gas dock and headed out. Sailed for a few hours then started up. After an hour and a half crossing running about 1500rpm I reduced to idle and entered a harbor with a crowded mooring field. Lots of onlookers. After 5-10 min the engine sputtered a bit, rpms would sink then bounce up to 1200 or so for a moment. Before I could reach the throttle it stalled out. A4 would turn over but not start, acted like it needed choke …or was flooded…no gas odor. Choke did not help. As we were drifting through a mooring field toward rocks I anchored. After about 30 min started up as if nothing was wrong. Idled smooth for about 30min then eventually puttered and stalled out in the same way. Got a tow home. Since then I have been down for clean-up and poked at the engine with no results. All appears normal, spark test ok. It started as usual, idled for 30 min without issue. I have the same concerns…maybe water in fuel after winter from tank condensation, fueling stirred up sediment or water overwhelming the racor, polishing filter or clogging the idle circuit, vapor-lock. Suggestions on a path forward to eliminate suspects and find the culprit appreciated.

              Comment

              • capnward
                Afourian MVP
                • Aug 2012
                • 335

                #8
                Theo,
                I think you are on the right track with suspecting a fuel clog. In my experience that is the usual problem with these engines. Drain your Racor to see if it has a lot of water in the bowl. If so, either you got some wet fuel, or water condensed out in your tank over the winter, or water got into your fuel intake. Then clean the jets in your carb, including the idle ports in the carb throat, and reassemble. Also check the float valve. While you're at it replace the inline (polishing) filters. Rebuilding (cleaning) the carb is something I do every spring. I also replace the Racor and inline filters then. I don't know how rough the water was during your hour and a half crossing. That could have stirred up junk in the tank. If enough junk got past the filters, it would be in the carb jets.
                Another possibility is your tank vent is clogged and the fuel pump can't suck out the gas. That is less likely. If you run the engine with the fuel intake cover off and it doesn't shut down, you will determine that. Blowing backwards through the fuel line (ick) with the fuel cap on tight may unclog the vent. If the vent is really clogged, you will get back pressure.
                Also, if you have an adjustable main jet, turning it into the seat and back out (1.5 turns, more to make it richer) may dislodge a blockage there.
                Good Luck!
                Attached Files

                Comment

                • Sam
                  Afourian MVP
                  • Apr 2010
                  • 323

                  #9
                  You have great advise above and normally the old engineering side of me would say follow the testing protocol. Instead based on my past similar problems/solutions my best additional guess is water/gunk in bottom of fuel tank or weak/faulty condenser.

                  Comment

                  • Theo Lewis
                    Senior Member
                    • Jan 2021
                    • 12

                    #10
                    Breadcrumbs

                    Leaving an outcome here for those who come later as I found many threads exactly like this one but no happy endings. After taking stock of my situation and the poor condition of the many parts that advice indicated might cause what I am calling a hot, slow shut-down I made a parts purchase: cap, rotor, plugs, coil, wires, fuel filters, carb parts and gaskets. Most are advisable as annual maintenance anyway. I did discover that contrary to what a mechanic told me last year I do in fact have an Ignitor EI installed, albeit badly with no notch filed in the cap. It caused the dist. cap to seat crooked and had let in moisture. Lots of arc burns and corrosion. I also figured out how to replicate the problem reliably. Heated up the engine by running against the mooring lines at 1500 for 20 min, drop to idle and wait. Within a few minutes it would start missing, sputter, eventually die and refuse to restart.
                    First installed the spare coil with no luck, then worked through most of the list with no joy. After a return to the forum I had another look at the coils. The first one tested out at 3ohm, the spare at 3.3 ohm. As running lower ohm coils without the additional external resistor will burn out a coil I see it seems both my first and spare were inadequate. I also suspect the spare that came with the boat was just an old burnt out unit left on the boat. I swapped in the new coil from MMI which did the trick. Have since completed “sea trials” by heating up as described several times, no stalling at idle. Have run at idle in and out of gear for hours, shifting in and out of forward attempting to coax a stall. Even adjusted idle down to 800 and ran through the whole deal again. This problem, at least for me, was, a burnt out coil which would work when cool and fail when it heated up. Thanks for the counsel and encouragement.
                    Last edited by Theo Lewis; 10-03-2022, 02:52 AM. Reason: Sp.

                    Comment

                    • joe_db
                      Afourian MVP
                      • May 2009
                      • 4474

                      #11
                      Originally posted by Theo Lewis View Post
                      Leaving an outcome here for those who come later as I found many threads exactly like this one but no happy endings. After taking stock of my situation and the poor condition of the many parts that advice indicated might cause what I am calling a hot, slow shut-down I made a parts purchase: cap, rotor, plugs, coil, wires, fuel filters, carb parts and gaskets. Most are advisable as annual maintenance anyway. I did discover that contrary to what a mechanic told me last year I do in fact have an Ignitor EI installed, albeit badly with no notch filed in the cap. It caused the dist. cap to seat crooked and had let in moisture. Lots of arc burns and corrosion. I also figured out how to replicate the problem reliably. Heated up the engine by running against the mooring lines at 1500 for 20 min, drop to idle and wait. Within a few minutes it would start missing, sputter, eventually die and refuse to restart.
                      First installed the spare coil with no luck, then worked through most of the list with no joy. After a return to the forum I had another look at the coils. The first one tested out at 3ohm, the spare at 3.3 ohm. As running lower ohm coils without the additional external resistor will burn out a coil I see it seems both my first and spare were inadequate. I also suspect the spare that came with the boat was just an old burnt out unit left on the boat. I swapped in the new coil from MMI which did the trick. Have since completed “sea trials” by heating up as described several times, no stalling at idle. Have run at idle in and out of gear for hours, shifting in and out of forward attempting to coax a stall. Even adjusted idle down to 800 and ran through the whole deal again. This problem, at least for me, was, a burnt out coil which would work when cool and fail when it heated up. Thanks for the counsel and encouragement.
                      That is an absolutely classic problem. To make matters worse, back in the day the Ignitor company recommended coils that were low resistance and WOULD burn out. As is the case with more than one product, the Moyer version saves you a lot of research and testing on your own, we know it works.
                      Joe Della Barba
                      Coquina
                      C&C 35 MK I
                      Maryland USA

                      Comment

                      • ndutton
                        Afourian MVP
                        • May 2009
                        • 9601

                        #12
                        Theo, please read this post from a few years ago. Moyer coil or not, running the calculation described in the post is recommended to prevent an eventual repeat of what you just experienced. Too bad your previous owner didn't do it.
                        Neil
                        1977 Catalina 30
                        San Pedro, California
                        prior boats 1987 Westsail 32, 1970 Catalina 22
                        Had my hands in a few others

                        Comment

                        • TimBSmith
                          Afourian MVP
                          • Aug 2020
                          • 162

                          #13
                          Neil that entire thread is pure educational gold on ignition, coil, ballast, EI, etc.

                          Thank you.
                          Tim Smith
                          Oasis
                          Pearson 30
                          1974, Number 572
                          Boston, MA USA

                          Comment

                          • ndutton
                            Afourian MVP
                            • May 2009
                            • 9601

                            #14
                            Thank you for the kind words Tim. The goal was to be as accurate, informative and helpful as possible. Also, I had a LOT of help from forum members. It took a few years of testing to get a grip on it but the end result has been a bullet proof solution with zero recurrence for those who followed the recommendations faithfully.

                            My very first post on this forum in 2009 was something to the effect of, "if electronic ignition is so great, why do you all carry your original points plate as a backup to get home when it fails?" My engine had points when I bought the boat and I was motivated to "upgrade" to EI but not if failure was all but guaranteed. What would be the point in that? Something had to be done so we set to work.
                            Neil
                            1977 Catalina 30
                            San Pedro, California
                            prior boats 1987 Westsail 32, 1970 Catalina 22
                            Had my hands in a few others

                            Comment

                            • W2ET
                              Former Admin
                              • Oct 2008
                              • 170

                              #15
                              This thread is arguably the most consequential of the eight thousand or so which have been posted over the eighteen years the forum has been up and running.

                              Bill

                              Comment

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