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  1. 03-21-2022, 06:29 PM #1
    stormzm
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    2011 250 Pro XS - Low RPM at WOT

    <1B903220>

    First post ever on a forum so bear with me.

    2011 250 Pro Xs on a 2011 Nitro Z8, brand new OEM torque master Lower spring of 21. About 285 hours on motor.

    ran 70+ last spring/summer, slowly started to loose holeshot then top speed

    Currently runs 52 mph and will not turn over 4800 RPMs at WOT. No matter what. Set the motor way too high with the jackplate, 4800 RPMs with a giant rooster tail and less speed.

    Has been to 2 different shops in the last 6 months. First shop replaced torn tracker valve, which fixed the sight miss at idle that it had but still only 4800 rpm. Took it back and shop called a month later and said they cannot find anything wrong and come get it. ��*♂️

    Took it to shop #2 a month ago, called next day and said they found a torn air pressure regulator diaphragm and they were sure that was my issue. We were unable to run the boat on the water because lakes were froze up. Took it out yesterday finally, 4800 rpm, 52mph. No difference.

    Any ideas on what could be wrong? Both shops have checked everything they can think of and about the only thing I haven’t done or had done is flow test and clean the injectors. Talked to Brucato injector service and he said basically he would do them for me but he was 95% sure they are not my issue.

    Anyone else have this problem before?
    Last edited by EuropeanAM; 03-23-2022 at 06:28 PM. Reason: Forgot serial #
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  2. DewRonInc
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    #2 03-21-2022, 09:54 PM
    Need to check coils
    Ron Fears
    Stroker/300XS
    1E003823
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  3. DewRonInc
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    #3 03-21-2022, 09:54 PM
    Also compressor, have u had injectors and rails cleaned
    Ron Fears
    Stroker/300XS
    1E003823
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  4. JOE54
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    #4 03-22-2022, 09:12 AM
    good spark ,good fuel/air psi delivery, all sensors and switches verified = procede to cylinder inspection /reed inspection ....... every da..n day i have it
    .................................................. ...the scariest thing in life is the unknown ...................................
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  5. stormzm
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    #5 03-22-2022, 09:59 AM
    So I did do a reed inspection and this is what I found… I know it’s not perfect but it doesn’t seem to me that the at could be my issue. Appears to still be sealing. Probably a good idea to replace anyway.
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  6. JOE54
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    #6 03-22-2022, 10:45 AM
    yes ,but not issue, pull plugs lets see um , note cyls they came from
    .................................................. ...the scariest thing in life is the unknown ...................................
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  7. castforcash
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    #7 03-22-2022, 10:51 AM
    Possibly a spun sleeve?!?
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  8. JOE54
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    #8 03-22-2022, 10:56 AM
    mind reader ^^^^^^
    .................................................. ...the scariest thing in life is the unknown ...................................
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  9. EuropeanAM
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    #9 03-22-2022, 11:35 AM
    If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
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  10. stormzm
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    #10 03-22-2022, 06:40 PM
    Newbie sorry! 😬 serial # 1B903220
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  11. leonreno
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    #11 03-23-2022, 02:42 PM
    Have you checked your fuel lines:
    http://www.bbcboards.net/showthread.php?t=22490
    Mercury 2002 200hp Carbed Saltwater
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  12. EuropeanAM
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    #12 03-23-2022, 06:31 PM
    Additionally: ALL of the BASICS been checked (as in during the last week): Compression Test, Spark Test, Fuel Quality, Delivery, Air/Fuel Pressure Tests, Reeds that are damaged replaced?

    Have the SPARK PLUGS been replaced since the diaphragm failures? If not... you probably need to.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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  13. stormzm
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    #13 03-23-2022, 07:09 PM
    Basics have all been checked each cylinder is 118lbs of compression… reeds are on their way. Going to borescope cylinders this weekend to check sleeve alignment. Planning on sending injectors out for cleaning and testing as well. Spark plugs are brand new NGK iridium’s that Mercury calls for. Air and fuel pressures are spot on
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  14. castforcash
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    #14 03-24-2022, 05:55 AM
    Quote Originally Posted by stormzm View Post
    Basics have all been checked each cylinder is 118lbs of compression… reeds are on their way. Going to borescope cylinders this weekend to check sleeve alignment. Planning on sending injectors out for cleaning and testing as well. Spark plugs are brand new NGK iridium’s that Mercury calls for. Air and fuel pressures are spot on
    Where did you buy your spark plugs? There have been some plugs sourced through auto parts stores that are not the same even though they are labeled the same.
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  15. EuropeanAM
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    #15 03-24-2022, 07:27 AM
    Take a very close look around the heads and the spark plug openings for any signs of water spotting, OR CRACKS. Saw a few in that vintage with hairline fractures to the water jacket, which would literally ground out the plug at higher RPM's (but were virtually undetectable at idle or low RPM's, other than the water spotting/stains).


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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  16. SilverFox579
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    #16 03-25-2022, 10:06 AM
    ^^^^

    See this topic for pictures of what Don posted about - 2007 Pro XS - reduced power - 2500 rpm
    _______

    Phil
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    '09 150 Optimax

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  17. Savage
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    #17 03-25-2022, 11:46 AM
    Quote Originally Posted by castforcash View Post
    Possibly a spun sleeve?!?
    Hmmmmmm I would pull heads and check at this point.......Takes 30 minutes to find out.


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  18. stormzm
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    #18 03-25-2022, 05:16 PM
    100% a spun sleeve…. Dang it!… Borescope shows it clear as a bell in Cylinder 6…. Going to start tearing it apart tonight
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  19. stormzm
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    #19 03-25-2022, 05:23 PM
    Attachment 484745
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  20. stormzm
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    #20 03-25-2022, 05:32 PM
    Is there any chance of rotating the sleeve back into position with heat/cold and some elbow grease or is it off to the machine shop I go? Not sure if you even got it to rotate if you could “stake” it back into place and trust it?
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