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2000 Mariner 90hp 2 stroke 3cyl knocking noise

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  • 2000 Mariner 90hp 2 stroke 3cyl knocking noise

    Hi.

    First sorry for my english because I'm French.

    We have a 2000 Mariner engine 90hp 2 stroke 3cyl, autolub, which has a knocking noise.
    When we bought it, we had to make the maintenance on it.
    At this moment, we noticed that the piston of the middle cylinder was overheating due to an oil injection failure. But the engine could run.
    So, we solved the oil injection problem and we replaced the 3 pistons + rings.

    We hear the knocking noise in neutral, it sound like a connecting rod but the noise doesn't increase with rpm. We don't hear it in gear (or it is lower and covered very well by the engine sound).
    The noise is from the powerhead (lower unit is rebuilt as new, drive shaft is new and we have removed the lower unit). The noise seems to be from the lower middle of the powerhead (heard with a screwdriver).

    Spark plugs are new, the ignition was adjusted with the strobe light.

    Thanks for help
    Regards

    EDIT : no connecting rod play.
    Last edited by Fan83; 01-04-2016, 02:28 PM.

  • #2
    You only hear the knock in neutral.

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    • #3
      may be piston slap if you did not bore the bad cly correctly or not at all

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