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Engine shut down at 4,000 rpm.

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  • Engine shut down at 4,000 rpm.

    Hello fellow I boaters. What I have is a 1985 bayliner capri with omc 5.0 liter with a 800 series out drive with a quadrajet 4 bbl carb.

    Last trip out to the lake every thing was great until I was pulling a skier at 30 mph and 4000 rpm and the boat engine just cut out like some one turned the key off. It started right back up and idled like normal. I pulled the skier in and we took off to shore to check the boat. The temp was normal at 160 the gas tank was full and the battery connections were tight so I set out for a test drive. the boat will plain well and start to get up to speed at wot and then at 4000 rpm will fall on it's face, but this time I pulled back on the throttle real fast and it cought it self and went back to idle.

    So I put the boat on the trailor to take it home and check thing's out later.

    Since this has happend I used the search function and found the fuel system test by another member good stuff there. So I have replaced the water fuel separator which I always do the year before while I winterize the boat. I have replaced the filter in the front off the carb which i usaully replace every hundred hours. I have also check the tank pick up which does not have a screen on it for some reason. I also checked the anti syphon valve.

    One question is, the anti syphon valve sapposed to be a little hard to blow thru because of the check ball in them? Mine has some resistance.
    Iam pretty sure this is a fuel problem and Iam a just trying to get some advice from the pro's.

    One other problem I found this year while boating , this was the first trip out this summer, the cutting out happend the fourth time
    was that it has developed a stumble when I give it wot from off idle it sound's like the the secondaries are opening and then away we go like a bad accelerator pump.

    do you guy's think since my fuel system up to the carb is good that this could be just my carb starting to act up? Time for a rebuild? Thank's in advance for any help Jered


  • #2
    Re: Engine shut down at 4,000 rpm.

    I have a 1996 Bayliner and just had a similar problem this weekend. All is well until 3000 - 4000 RPMs then a complete shutdown. I replaced the fuel filter located in the carb. It was full of what looked like fine sand. The Marina told me it was from the Ethenol in the fuel. Older boats engines were not made to run on gas with ethenol. I added a fuel additive (don't have the name with me right now) and still had the problem until the additive worked its way into the carb. I think a good carb cleaner may have helped -- but i was on the water. The Anti-sipon valve is hard to blow thru, but if you take it off you should just replace it and check the fuel feed line from anti siphon valve to fuel pump.

    Comment



    • #3
      Re: Engine shut down at 4,000 rpm.

      Another possibility is a fuel tank venting issue. You could try running with the gas cap off to see if it does the same thing.
      1998 Wellcraft Eclipse 24 Cuddy
      Volvo Penta Duo-Prop 7.4L "LK"

      2006 Sun Tracker Party Barge 21
      Mercury 90 4-Stroke FI
      "Common sense is not very common"
      "Failing to prepare is preparing to fail." -- John Wooden

      Comment



      • #4
        Re: Engine shut down at 4,000 rpm.

        Originally posted by dlac90 View Post
        I have a 1996 Bayliner and just had a similar problem this weekend. All is well until 3000 - 4000 RPMs then a complete shutdown. I replaced the fuel filter located in the carb. It was full of what looked like fine sand. The Marina told me it was from the Ethenol in the fuel. Older boats engines were not made to run on gas with ethenol. I added a fuel additive (don't have the name with me right now) and still had the problem until the additive worked its way into the carb. I think a good carb cleaner may have helped -- but i was on the water. The Anti-sipon valve is hard to blow thru, but if you take it off you should just replace it and check the fuel feed line from anti siphon valve to fuel pump.
        I will add a bottle of carb cleaner-fuel system cleaner when I fill up to take it for a test drive and see if that help's.

        I will also remove the gas cap this weekend as well.

        I did spray out the anti syphon valve with carb cleaner before I put back in. I also have checked the fuel lines for possible stuff blocking it. Rubber and hard lines. Thank's for response keep them coming. Jered

        Comment



        • #5
          Re: Engine shut down at 4,000 rpm.

          JP Listening to your discription,,,,You say it's like someone turned the key off. Not it couldn't go any faster and started to stumble, cough, run lean,,. If it was carb, or lack of gas,,, wouldn't it want to go lean? Then, as soon as you started to close the butterflys back, then it would return to it's 3800 rpms?
          The boat does start to go under a very heavy load at 4000rpms. Some times spark won't jump if the pressure is to extreme.
          I'm not sure it's carb,,, but I'm not sure what the electic part would be failing. Hang in there. Someone will have it.

          Comment



          • #6
            Re: Engine shut down at 4,000 rpm.

            Originally posted by Holy Smoke View Post
            JP Listening to your discription,,,,You say it's like someone turned the key off. Not it couldn't go any faster and started to stumble, cough, run lean,,. If it was carb, or lack of gas,,, wouldn't it want to go lean? Then, as soon as you started to close the butterflys back, then it would return to it's 3800 rpms?
            The boat does start to go under a very heavy load at 4000rpms. Some times spark won't jump if the pressure is to extreme.
            I'm not sure it's carb,,, but I'm not sure what the electic part would be failing. Hang in there. Someone will have it.
            You do make a very good point. I did pay a marine shop to replace some ignition componets at the end of last season when I had it winteriezed. But they did not replace every thing. I know they did the cap rotor plug's wires, but I do not think they replaced the condensor. I could be wrong I would haft to check my work order first. but even if they did does not mean that my timming and dwel are set correctly.

            Iam going to use the search function and see what I can find on ignition diag. Thank's for the response. Jered

            Comment



            • #7
              Re: Engine shut down at 4,000 rpm.

              I am going with the description that it is like someone turned off the key, that is not typically a symptom of a fuel problem, more like an electrical problem.

              If the boat has a deadman safety switch you might check that out.

              There is also a shift assist switch or module on OMC's like yours that can cause that type of symptom.

              If it has a tach wire hooked to the negative coil terminal, usually a gray wire, then try unhooking that. In dash tachs can go bad internally and interfere with the points triggering the coil.

              A coil can act like that also.

              Just some things to think about, sorry I cannot be more specific.
              1991 HydroSwift 2200 Cuddy Volvo Penta 570/DP
              1980 Glastron SSV167 90HP Mariner

              Comment



              • #8
                Re: Engine shut down at 4,000 rpm.

                Originally posted by Maclin View Post
                I am going with the description that it is like someone turned off the key, that is not typically a symptom of a fuel problem, more like an electrical problem.

                If the boat has a deadman safety switch you might check that out.

                There is also a shift assist switch or module on OMC's like yours that can cause that type of symptom.

                If it has a tach wire hooked to the negative coil terminal, usually a gray wire, then try unhooking that. In dash tachs can go bad internally and interfere with the points triggering the coil.

                A coil can act like that also.

                Just some things to think about, sorry I cannot be more specific.
                I was reading my repair manuel today and was reading about the shift assist switch. I will look there. This weekend I will also remove the tach wire to see if that help's. But I have never heard of a dead man switch? Can you go into further discription on that one for me. I am going to try thing's in order one at a time to see if any of them help. it just suck's cause I can't wait until the weekend to get it on the water to fix it that suck's. But then I do not want to get to far away from the shore incase some thing happens and the boat just stop's running. Thank's for the response Jered

                Comment



                • #9
                  Re: Engine shut down at 4,000 rpm.

                  Jetskis and other PWC's have them, and some boats do. It is called a personal safety switch or something like that, my brain is fuzzing out here....but some boats have one also. Besides the igniton key there is a key with a lanyard that plugs into a jack on the helm control. The engine will not run unless that key is in the jack. The lanyard is intended to be attached to the operator's wrist, the idea is to kill the engine if the operator goes overboard.
                  1991 HydroSwift 2200 Cuddy Volvo Penta 570/DP
                  1980 Glastron SSV167 90HP Mariner

                  Comment



                  • #10
                    Re: Engine shut down at 4,000 rpm.

                    Originally posted by Maclin View Post
                    Jetskis and other PWC's have them, and some boats do. It is called a personal safety switch or something like that, my brain is fuzzing out here....but some boats have one also. Besides the igniton key there is a key with a lanyard that plugs into a jack on the helm control. The engine will not run unless that key is in the jack. The lanyard is intended to be attached to the operator's wrist, the idea is to kill the engine if the operator goes overboard.
                    I have check the helm cotrol and did not find one. I really do not belive I have a dead man cut out switch. but thank you for the advice. Jered

                    Comment

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