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Opinoins please .. Run it or Not?

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  • Opinoins please .. Run it or Not?

    So after a few sets today I was heading back to the slip to put her away and running around 3000 rpm's I noticed a ticking noise that sounded like it was coming from the engine compartment. Opened the hatch while underway and there was a pretty loud knocking noise. Not ticking, more like knocking almost like a lifter went bad.

    After getting it back to my slip I called my Marine Mechanic who was on site. He came over and diagnosed a bad exhaust gasket.

    Now here is the weird part. After idling a bit and when under idle I was manuevering to park my boat after a quick test run with the mechanic and it started to run rough. We shut it off and started it back up and the roughness went away.

    His interpolation was that there must be a knock sensor and the exhaust leak was tripping it and therefor retarding the timing and making it run rough.

    So I said, well, no boat this weekend His reply was the opposite. He said run it. With a little tunes and the cover closed you can't hear it at all and even without the radio and the cover shut its pretty faint. Open is a totally different story.

    There is no knocking when under 1500 rpms. Oil pressure is great, Temp is great.

    Opinoins: Run it or Not this weekend?

    Thanks guys
    sigpic
    When I was a child, I used to talk as a child, think as a child, reason as a child; when I became a man, I put aside childish things.
    1 Corinthians Chapter 13 - 11

  • #2
    Heck No

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    • #3
      No, not at all

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      • #4
        Not until you know exactly what is knocking. Way too risky.
        Bob

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        • #5
          My marine mechanic is top notch. So I really need some guts other than the plain old, you need to know first. I know. It's not a rod or lifter.


          Sent from my HTC One using Tapatalk 2
          sigpic
          When I was a child, I used to talk as a child, think as a child, reason as a child; when I became a man, I put aside childish things.
          1 Corinthians Chapter 13 - 11

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          • #6
            My main concern is how it's tripping the knock sensor and retarding the timing. My risers have been dealing for a while.

            Also, I'm not going to hold anyone accountable if my engine blows. Which it won't. We drove it at least 3 miles and no gauges were reading bad, no vibration could be felt on the heads or valve covers.

            Sent from my HTC One using Tapatalk 2
            sigpic
            When I was a child, I used to talk as a child, think as a child, reason as a child; when I became a man, I put aside childish things.
            1 Corinthians Chapter 13 - 11

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            • #7
              I say give Mike G. some gas and make him drive.
              I spent most of my money on booze, broads and boats. The rest I wasted. - Elmore Leonard

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              • #8
                Disconnect the wire to knock sensor so it won't retard the spark when it hears the click. I can't get out till sunday to look at it with you. I would run to auto parts store and get a machanics stethascope or a long screwdriver and give your engine the once over to if it's clicking quieter at idle.

                Was it a popping noise or clacking (metal against metal). regardless you won't get any performance with the knock sensor sending positive knock data to ECU.

                Hopefully it's just a tired manifold or riser gasket - or at most a need for a new set of manifolds and risers...officially they are rated for 500 hours - but many get many more hours out of them.

                Bad Riser seals will let water back into cylinders - not a good thing
                sigpic...A bad day water skiing still beats a good day at work...1995 Pro Star 205....

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                • #9
                  Originally posted by madcityskier View Post
                  I say give Mike G. some gas and make him drive.
                  Good idea for Sunday... we can wake but no surfing...
                  sigpic...A bad day water skiing still beats a good day at work...1995 Pro Star 205....

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                  • #10
                    stupid question but did you check the oil was it milky looking, had a friend with bad gaskets and the water got in the oil.

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                    • #11
                      Originally posted by uplander View Post
                      stupid question but did you check the oil was it milky looking, had a friend with bad gaskets and the water got in the oil.

                      Yes checked oil. Was not milky in any way. Or low or dirty. Beautiful in fact.

                      I guess it's more of a pop than knock.

                      We did locate the noise to be an exhaust leak. My mechanic and I spent about 25 minutes running up and down the river. At all different rpms. I never noticed a loss in power.

                      Sent from my HTC One using Tapatalk 2
                      sigpic
                      When I was a child, I used to talk as a child, think as a child, reason as a child; when I became a man, I put aside childish things.
                      1 Corinthians Chapter 13 - 11

                      Comment


                      • #12
                        I don't "think" an exhaust leak would cause a big enough harmonic noise in the block to trip the knock sensor. 95 EFI does have a knock sensor in one of the block drain plugs.
                        If you ran it again with the exh leak and not running rough it may have just been an anomoly that it ran rough the first time.
                        You dont say which gasket. Manifold to head or manifold to riser?
                        Mike is correct on the riser gasket could potentially be blown out on the inside surface as well and allow water into the dry side of the exhaust.
                        If it's the gasket on the head then run it as long as it's not a big exhaust leak, maybe leave the blower on, think CO2 in the engine box.
                        Either way it's theoratically a simple fix save for every exhaust seems to have stubborn rusty bolts that wont come out or break.
                        I'd park it and start hitting the bolts with penetrating oil. Trick to getting out rusty exhaust bolts. If you can heat up the portion that the boltis threaded into head or manifold and not the bolt per se, with a cutting torch (even Mapp gas will work but will take alot longer) you can usually remove the bolt easily because the piece the bolt is threaded into expands slightly braking the rust bond in the threads.
                        '06 X2 MCX

                        "I understand why some people may not want to do this the way I have recommended but I can't understand the death grip some people have on a toilet plunger with a hose fitting." -JimN

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                        • #13
                          If you run it, then you will definitely find out what the problem is then!

                          How old is the knock sensor?

                          Put it this way though, motor cannot get any BETTER by running it at this point. Can he hook it up to the computer and see if any codes are coming thru?



                          I have an extra knock sensor if you want to test it with...

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                          • #14
                            It is the gasket on the head. My manifold to riser gaskets are seeping but not leaking like crazy or anything.

                            Maybe the sound with the cover down tripped the knock sensor. The problem is on the port side.

                            My knock sensor is original. So Rockman I might take you up on that

                            We did hook it up to see if any codes were thrown and nothing at all came up.

                            Sent from my HTC One using Tapatalk 2
                            sigpic
                            When I was a child, I used to talk as a child, think as a child, reason as a child; when I became a man, I put aside childish things.
                            1 Corinthians Chapter 13 - 11

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                            • #15
                              Did you pull all plugs to make sure water is not getting into the cylinder from a leaking riser gasket? I think you really want to rule that out. Hydro lock is a bad thing. Just went through this on a buddies Malibu. He got lucky and only blew the head gasket. It was a knocking noise like you describe and still ran (though roughly). Just something to consider.

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