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  • Boat starting issue - as in not starting normally...

    I was out Sunday and pushed the start/stop button and the boat just cranked. Did it a few more times, just cranked, no engine turnover. Then I remember a trick my dealer taught me, engage neutral button, more throttle forward and then crank - started up. Haven't tried it since then but is there an issue I should be aware of? I'm getting tired of calling my dealer to come rescue me...
    08 X30 - deader than dead...and crispy.

  • #2
    Sounds like a heat soak temp issue.. the throttle forward provides more fuel. Test coolant temp sensor.

    Also test thermostat for correct operation

    Sent from my SM-G955U using Tapatalk
    sigpic...A bad day water skiing still beats a good day at work...1995 Pro Star 205....

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    • #3
      Sounds like a fuel or air to fuel mixture issue.
      2016 X30

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      • #4
        Originally posted by DavidF View Post
        I was out Sunday and pushed the start/stop button and the boat just cranked. Did it a few more times, just cranked, no engine turnover. Then I remember a trick my dealer taught me, engage neutral button, more throttle forward and then crank - started up. Haven't tried it since then but is there an issue I should be aware of? I'm getting tired of calling my dealer to come rescue me...
        I agree that it sounds like a coolant temperature sensor- make sure to test the one that sends signal to the ECM.

        I stopped working at MC dealers in 2001, so I don't know the Ilmor engines, but since there's really no reason to reinvent the wheel, I suspect the gauge may have its own sender for temperature because that's only to alert the driver and won't change the state of the engine's operation via the ECM.

        If the exhaust smells of gasoline after the engine has run to normal operating temperature and especially if you see black sooty deposits on the transom, I would suspect the ECT. These and being able to start it by 'cracking the throttle' point directly to this diagnosis.

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        • #5
          Originally posted by mikeg205 View Post
          Sounds like a heat soak temp issue.. the throttle forward provides more fuel. Test coolant temp sensor.

          Also test thermostat for correct operation

          Sent from my SM-G955U using Tapatalk
          Cracking the throttle provides more air than when it's closed and affects the gas delivery only a little, if at all. At high temperature, the engine is supposed to run lean because it's more efficient than at low temperatures but if the ECT failsc and the ECM thinks the engine is cold, it will deliver too much fuel, which makes the engine hard to start. Opening the throttle corrects the air/fuel ratio, or at least comes close enough to make it run. If the throttle is only opened a bit, the TPS may show that it's out of the normal range for idle and/or crank mode (The GM system uses 0°-2° and 0-300 RPM to define 'crank mode with closed throttle') but the MAP sensor will see a change and the additional air will allow it to run.

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          • #6
            thanks
            08 X30 - deader than dead...and crispy.

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            • #7
              Originally posted by JimN View Post
              Cracking the throttle provides more air than when it's closed and affects the gas delivery only a little, if at all. At high temperature, the engine is supposed to run lean because it's more efficient than at low temperatures but if the ECT failsc and the ECM thinks the engine is cold, it will deliver too much fuel, which makes the engine hard to start. Opening the throttle corrects the air/fuel ratio, or at least comes close enough to make it run. If the throttle is only opened a bit, the TPS may show that it's out of the normal range for idle and/or crank mode (The GM system uses 0°-2° and 0-300 RPM to define 'crank mode with closed throttle') but the MAP sensor will see a change and the additional air will allow it to run.

              This is correct, and just to add to it....... If throttle is set at more than 3/4 while cranking, the ECU will go in to "Clear Flood" mode, and will actually stop fueling entirely.

              To the OP- This can happen once in a while with boats. It is normal if it only happens VERY infrequently. If it happens more often, you should check that air intakes to the engine compartment are free and clear, and that the engine is able to get plenty of fresh air. Running the blower can help bring in new air after sitting as well. There are other issues that can contribute, but i would start there.

              Which engine does this boat have? The 7.4 was more prone to this issue, but had revisions to the ECU software to help eliminate it.

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              • #8
                Originally posted by FourFourty View Post
                This is correct, and just to add to it....... If throttle is set at more than 3/4 while cranking, the ECU will go in to "Clear Flood" mode, and will actually stop fueling entirely.

                To the OP- This can happen once in a while with boats. It is normal if it only happens VERY infrequently. If it happens more often, you should check that air intakes to the engine compartment are free and clear, and that the engine is able to get plenty of fresh air. Running the blower can help bring in new air after sitting as well. There are other issues that can contribute, but i would start there.

                Which engine does this boat have? The 7.4 was more prone to this issue, but had revisions to the ECU software to help eliminate it.
                Usually, clear flood occurs at WOT, which is easy with an ECM because it has a TPS to tell it where the throttle is. With a carb, it works just as well because there's not enough vacuum below the carb to draw fuel in. I doubt the air intakes could be clogged enough to prevent it starting since a boat isn't a closed envelope.

                FWIW, the 2001 models had this problem because Rochester decided to omit the hole in the throttle plate, but they didn't let MC know about it. This required a recal, to open the IAC a bit but there's almost no chance that a boat without the recal would have been considered 'useful' for all of these years.

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                • #9
                  Originally posted by JimN View Post
                  Usually, clear flood occurs at WOT, which is easy with an ECM because it has a TPS to tell it where the throttle is. With a carb, it works just as well because there's not enough vacuum below the carb to draw fuel in. I doubt the air intakes could be clogged enough to prevent it starting since a boat isn't a closed envelope.

                  By far, the most common issue I have ever seen with hot start issues was a mouse nest in the fresh air intakes to the engine compartment.

                  Although they are not "closed envelope", insufficient supply of fresh air can cause major starting problems. If they are drawing a good amount of air (like when running), they are usually able to draw air from all the cracks/crevices/etc if the fresh air vents are plugged.

                  a good example of this is the 2014-2019 Prostars. They had a ton of issues with the early boats starting after the boat was left sitting warm. MC had to install an auxiliary fresh air fan that runs all the time when the key is on to get rid of the problem. These prostars had sufficient airflow to draw in when they were running, but air wouldnt exchange well while they were off and sitting still. It was just enough of an issue that they would have extended crank times, or failure to start after heat soak. They caught the issue pretty early, so there wasnt huge problems, but anyone who has that generation prostar knows they have an annoying fan running all the time.

                  While clear flood is generally known to activate in WOT, the software in the Ennovation Controls ECU will activate clear flood anything beyond 75% or so. I can watch the transition on my Diacom..... I'm not sure if Ilmor specifically set it that way, or if it is an industry standard to set the transition at 75%ish throttle. I know from my drivability diagnostic days on cars, it was a similar level of throttle percentage for the transition.

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                  • #10
                    Mine is a 2015 X30. It's new to me so not sure if this has happened to the previous owner. This is the first time since May that it's occurred and I haven't started it since as we left for the weekend. Will try again Friday and see if it's still an issue. Thanks again for all the replies.
                    08 X30 - deader than dead...and crispy.

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                    • #11
                      Originally posted by FourFourty View Post
                      By far, the most common issue I have ever seen with hot start issues was a mouse nest in the fresh air intakes to the engine compartment.

                      Although they are not "closed envelope", insufficient supply of fresh air can cause major starting problems. If they are drawing a good amount of air (like when running), they are usually able to draw air from all the cracks/crevices/etc if the fresh air vents are plugged.

                      a good example of this is the 2014-2019 Prostars. They had a ton of issues with the early boats starting after the boat was left sitting warm. MC had to install an auxiliary fresh air fan that runs all the time when the key is on to get rid of the problem. These prostars had sufficient airflow to draw in when they were running, but air wouldnt exchange well while they were off and sitting still. It was just enough of an issue that they would have extended crank times, or failure to start after heat soak. They caught the issue pretty early, so there wasnt huge problems, but anyone who has that generation prostar knows they have an annoying fan running all the time.

                      While clear flood is generally known to activate in WOT, the software in the Ennovation Controls ECU will activate clear flood anything beyond 75% or so. I can watch the transition on my Diacom..... I'm not sure if Ilmor specifically set it that way, or if it is an industry standard to set the transition at 75%ish throttle. I know from my drivability diagnostic days on cars, it was a similar level of throttle percentage for the transition.
                      While I haven't seen the newer boats, I have to say that I never saw a single boat with a nest in the intake. Might be a regional thing- I think the critters here are too fat & lazy from eating all Winter.

                      WRT clear flood- they may have changed the TPS point to 75%, but it's probably easier to remember to go WOT- end users won't know where 75% is unless it shows on the screen and they generally don't need to know that.

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