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  1. #1
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    2000 mercury 175 efi serial number OT101466

    Boat won't get on plane Boggs down. Compression good and equal on all cylinders. Replaced stator one rectifier. Cdi module firing on all six. If the boat does get on plane I'm loosing about ten mph. Any suggestions where to look next??

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    Welcome to BBC!

    Always a good idea to start with the BASICS: Compression Test, Spark Test, Fuel Quality/Delivery/PRESSURE tests.

    Fuel pressure readings should be monitored:

    -At idle
    -Under Acceleration
    -WHEN PROBLEM IS OCCURRING
    -15/30/60 Seconds after engine shutdown.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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    #3
    Compression 115 on all cylinders fuel pressure at 36on return. Will do the bleed test
    Spark has been erratic on #4,6 cylinder, put new cdi on 4 and 6.

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    #4
    Fuel pressure
    34 at idel
    15 seconds 33
    30 seconds 32
    60 seconds 30

  5. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #5
    Quote Originally Posted by Air Castle View Post
    Spark has been erratic on #4,6 cylinder, put new cdi on 4 and 6.
    Let's focus on this for a bit. How did you discover this- and what are you referring to as a "CDI" (possibly the CDM's aka: Coils)?


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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    #6
    Cdm. Gap test

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    #7
    Redone fuel pressure test and added bleed down

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #8
    Quote Originally Posted by Air Castle View Post
    Cdm. Gap test
    Keep in mind that CDM ignition coils (CDM's) with no spark on one or more cylinders are quite often the fault of a coil that IS firing. 1-2-3 are the return ground path for 4-5-6 (you probably need to go back to the spark test and make absolutely sure you've resolved the spark problem).

    Also keep in mind that when TWO cylinders have no spark or intermittent spark, it is quite possibly the TRIGGER or the TRIGGER HARNESS (trigger harness is known for becoming brittle and breaking wires inside the insulation).


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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    #9
    Will recheck in the morning. I appreciate your advice. What about the fuel pressure??

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    #10
    Still not firing on #6 cylinder weak on #5 cylinder

  11. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #11
    Check #1, 2 and 3 CDM's.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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