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  1. #1

    Default 1992 Alpha 1 knocking noise

    Hello,

    We just rebuilt out 1992 Alpha I Gen II motor (5.7L) and put a new water pump and oil in the out drive. All has been well until about 7 hours of operation the drive has developed a noise that sounds like someone is hitting it with a ball peen hammer at or very close to engine speed. It is not the deep down knock like comes from a rod bearing, but more than just a tap, tap, tap. We didn't pull the drive out yet, does anyone have a suggestion of what to look for first before pulling the drive? The drive is original, we replaced the water pump and changed the oil and that's it.

    Ideas?

    Thank you all very much!

    Kurt
    Calhoun, GA

  2. #2
    Join Date
    Jun 2006
    Location
    Spotswood, NJ, USA
    Posts
    3,823

    Default Re: 1992 Alpha 1 knocking noise

    rocker arm noise, loose, broken, pulled stud, bent pushrod, broken spring

  3. #3

    Default Re: 1992 Alpha 1 knocking noise

    Thanks, I am looking for causes of the noise from the out drive. That is where the noise comes from. The engine appears to run fine and is quiet.

  4. #4
    Join Date
    Jun 2006
    Location
    Spotswood, NJ, USA
    Posts
    3,823

    Default Re: 1992 Alpha 1 knocking noise

    a U joint getting ready to explode

  5. #5
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    4,567

    Default Re: 1992 Alpha 1 knocking noise

    Before you pull the drive run it on the hose and determine if it is the upper or lower.

    Remove the drive and fire up the engine, see if the noise goes away. Just to confirm it is the drive.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  6. #6

    Default Re: 1992 Alpha 1 knocking noise

    So you mean to just run the engine long enough to verify the noise is gone without fresh water, right?

  7. #7
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    4,567

    Default Re: 1992 Alpha 1 knocking noise

    Quote Originally Posted by Kurt30701 View Post
    So you mean to just run the engine long enough to verify the noise is gone without fresh water, right?
    You can run it with out water to verify. No harm will be done. Keep it under 30 seconds at a time.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

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