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  1. #1
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    2002 75 Hp ELPTO questions need help please

    Hello ,
    I have a Merc s/n OT463935 .
    Bought used dealer said ran good and has good compression
    90 psi all cylinders .
    I test my self I got 110 on my Guage.
    Problem is it ha always run like dog .
    Chugs smokes, no power .
    Performed cylinder drop test can pull top cylinder plug wire off runs same no change .
    Pull middle cylinder wire off engine dies .
    Pull bottom cylinder wire off no change.
    Pull top and bottom wire off both engine stays running?
    Seems like only runs on the center cylinder.
    Replaced every electric part on this motor plugs, coils, regulator, trigger , stator , engine wire loom . Rebuild carbs with Mercury kits had rubber needles in the carb replace with factory steel needles. Still starts and runs horable . ordered new motor because I gave up last season. Now this year have to try again because the new motor still has no eta .
    Any one have any ideas
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    Three (3) things are required to make the magic happen in the cylinder:

    -Fuel

    -Spark

    -Air (Compression is only part of this).

    I would recommend inspecting the REEDS. If you have reeds that are not closing properly or seating, it may prevent the crankcase from developing enough vacuum (low pressure or suction) to pull fuel and air through the venturi of the carb. At higher RPM's, the cylinders might come to life since reeds are progressively open more and more of the time (as RPM's increase).


    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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  3. Member
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    #3
    How can I tell if my carb float level is not to high and flooding.?
    Eng seams to run better level or tilted up if tilt is down.it runs worse.
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

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    #4
    see any fuel leaking from bowl vent ????? also that mtr has bleed system restrictor's behind reed plates that may be giving you a problem letting fuel build up in reed area when idling will act as if its flooding
    .................................................. ...the scariest thing in life is the unknown ...................................

  5. Member
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    #5
    How would the motor runn if flow was set to low ?
    I watched a you tube video when I rebuilt carbs and the video was not the same as the servce manual picture for the carb float setting .
    I am going to recheck floats this weekend. How would I test the bleed restrictions behind the reeds?
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

  6. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #6
    Float levels too low can cause fuel starvation at higher RPM's, poor idle quality, and even acceleration problems.

    No substitute for a Service Manual. Can't tell you how many "well meant" tube videos I've seen that were riddled with costly errors.


    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).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  7. Member
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    #7
    So I took carbs apart again check level on floats they were correct but I set the a hair lower just to be sure.
    Installed and pumped up primer bulb started motor still starts right up and runs on muffs ok but seamed still pig rich.
    Turned it off and raised the motor with tilt and watched the carb Opeings for about 5.min , noticed fuel running from center carb and drip down in the Cowl.
    Pulled back off removed and rechecked the carb needle found nothing wrong with the new needle but for sure not seal on the seat
    Had old one l removed last year different color orange instead of black , black was one from new mercury kit.
    Installed old orange needle got carb to stop leaking when tilt raised.
    Took for test ride got max 4000 rpm but still sounds like struggling to get max rpm Surge at full throttle.
    Still believe carbs are letting in to much un metered fuel . Something is wrong with the needles and seats.
    Not sure what to do this it will the fourth time I have had carbs off the engine if I go back in .
    Can seats be replaced with new on these
    Mercury carbs?
    Last edited by veryspeedy; 05-22-2022 at 03:00 PM. Reason: Spelling.
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #8
    Question: Have you replaced the floats in these carbs?

    Are you running a PORTABLE or a BUILT-IN fuel tank?


    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).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  9. Member
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    #9

    Re Carb issues 75 elpto

    Yes , but the old float not bad in any way.
    It has new floats . Had all new Mercury Carb kits installed in 2021
    After this past weekend I am 99 percent sure the carbs are not
    Deliving fuel correct.
    I have triple checked the float levels carbs apart 3
    Times .
    Carbs seam to be still allowing fuel unmetered.
    No debrie in carbs was found ,
    Sprayed out carb jets and orifice when they were apart with gum out.
    Pontoon 25 gal gas tank , running fresh boat gas
    Fuel smell and fuel oil slick behind boat when just turned off and sit at dock.
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

  10. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #10
    Just so we're not making any assumptions:

    Please verify that item# 18 as shown in the below diagram is IN PLACE and in good condition.

    Attached Images Attached Images


    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).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  11. Member
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    #11
    Yes verified all #18 on all three carbs is in place.
    On other carbs I have worked on in the.past you could replace
    The needle and seat as a matched set.
    This carb, only the needle makes no sense to me.
    I am 51 and been working on carbs since I was 16 mostly Holley performance automotive.
    I just think this carbs might have a warped unit or a bad seat .
    Just something I can't see .
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

  12. Member
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    #12
    Let me ask this this is a 75 Hp running a 14x11p prop on a 20 foot pontoon (heavy boat)
    Hole shot is decent but at full throttle can't get 4000 rpm .
    Seams like Surging at full throttle rpm between 3500 and 3900 . On crappy dash tach.
    Top speed is 8.5 on gps, shouldn't this run mid to upper teens for mph?
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

  13. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #13
    Don't trust the analog tach... an inductive pickup tachometer (such as is used in many timing lights, or the "Tiny Tach" would be far more accurate).

    Confirmed that all three (3) carbs are advancing to throttle plates LEVEL in the bore at WOT position?

    And yes- the seat is not a replaceable unit in those carbs. Very rare that one is needed (usually the needle that gives a problem, OR the tang on the float develops a "divot" that the end of the needle can hang in, resulting in poor or erratic needle seating.


    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).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  14. Member
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    #14
    Ordered a tiny tach off <EDIT>, should be here for the weekend attack on this problem again.
    I will double check shutters nd linkage .
    Some one asked me what the plugs look like and honestly they always look clean like they did when I put them in.
    my plugs in my Evinrude come out looking brown to black , but this Mercury always look clean .
    Could this be a head gasket issue ?
    Last edited by EuropeanAM; 05-26-2022 at 05:07 PM.
    CJ
    200 Evinrude G2 Ho On R93vs Ranger

  15. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #15
    Unlikely, but not impossible.


    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).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor