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  1. #1
    Join Date
    Sep 2019
    Location
    toronto
    Posts
    19

    Default Need help. Why 20hp mariner 2 cylinder motor runs slow

    Hi all friend.

    This morning i tested the 2 cylinder and getting both 120psi. But on full speed but my speed is only 11 to 13km/hr.

    Any suggestion please

  2. #2
    Join Date
    May 2015
    Posts
    2,360

    Default Re: Need help. Why 20hp mariner 2 cylinder motor runs slow

    Check for spark sounds like it is running on one cylinder.

  3. #3
    Join Date
    Sep 2019
    Location
    toronto
    Posts
    19

    Default Re: Need help. Why 20hp mariner 2 cylinder motor runs slow

    Quote Originally Posted by flyingscott View Post
    Check for spark sounds like it is running on one cylinder.
    Can you or some one guide me how to check?

    Thanks

  4. #4
    Join Date
    May 2015
    Posts
    2,360

    Default Re: Need help. Why 20hp mariner 2 cylinder motor runs slow

    With the motor running pull one spark plug wire off at a time. Use a plastic pliers to pull the wires off. It should be able to idle on one cylinder at a time. Report back results.

  5. #5
    Join Date
    Sep 2019
    Location
    toronto
    Posts
    19

    Default Re: Need help. Why 20hp mariner 2 cylinder motor runs slow

    Quote Originally Posted by flyingscott View Post
    With the motor running pull one spark plug wire off at a time. Use a plastic pliers to pull the wires off. It should be able to idle on one cylinder at a time. Report back results.
    Ok when engine running i tried take the one plg out, sound was less but engine was keep running, turn off the engine, put the plug back in, atart the engine, now took the other plug out, same sound was less but engine was keep running, tested before both cylinder got 125psi.

    What could be the issue?

  6. #6
    Join Date
    Sep 2019
    Location
    toronto
    Posts
    19

    Default Re: Need help. Why 20hp mariner 2 cylinder motor runs slow

    Quote Originally Posted by flyingscott View Post
    With the motor running pull one spark plug wire off at a time. Use a plastic pliers to pull the wires off. It should be able to idle on one cylinder at a time. Report back results.
    Ok when engine running i tried take the one plug out, sound was less but engine was keep running, turn off the engine, put the plug back in, start the engine, now took the other plug out, same sound was less but engine was keep running, tested before both cylinder got 125psi.

    What could be the issue?

  7. #7
    Join Date
    Sep 2019
    Location
    toronto
    Posts
    19

    Default Re: Need help. Why 20hp mariner 2 cylinder motor runs slow

    Quote Originally Posted by flyingscott View Post
    With the motor running pull one spark plug wire off at a time. Use a plastic pliers to pull the wires off. It should be able to idle on one cylinder at a time. Report back results.
    Hi all, just to update i clean the Carb, rebuild with original gaskit, bought from mercury, but progress doesnt change after few start engine doenst start, amd speed ia the same 11 to 13 km/hr, i dont know what else i have to do.



    Any suggestion.

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