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  1. #1
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    1991 Mercury 150 Accelerator Pump rebuild kit

    Hello,

    I recently bought a 150 HP Mercury with carbs (Serial #: D050150 - see pics with number on freeze plug).
    I would like to rebuild/baseline the carbs completely and this particular model has carbs with accelerator pumps.
    Looking at the parts breakdown on the carbs it looks like there is a cup assembly but it's NLA (no longer available).
    Cup assembly part number: 810762

    What is my path forward on replacing the cup assembly?
    Any aftermarket or superceded part options?

    Thanks for any help you can provide.

    20221029_004748.jpg
    20221116_103608.jpg

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    #2
    you should be able to just replace rubber part of the pump and retain that piece
    .................................................. ...the scariest thing in life is the unknown ...................................

  3. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #3
    It's NLA... but I just PM'ed you a lead on the one dealer that has said they have a few left in stock.


    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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    #4
    Thanks Don! they had them in stock!
    Ordered..

  5. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #5
    Wahoo! Glad that worked out for you!


    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

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    #6
    Quick questions:

    1. After rebuilding the carbs, apparently the clip that attaches the needle valves to the float tang were ALL missing.
    Are these clips included in the needle and seat kits?
    If not, are they sold seperately?

    2. What is the reccomended max timing at cranking speed? My service manual states 19 deg BTDC. Note: the oil injection and idle stabilization units have been removed by the previous owner. Is a different timing reccomended for safe operation (I'm looking for long term reliability not racing type performance).

    Thanks again.

  7. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #7
    I don't believe the spring clips were used on these (the needle MAY have a place for it, but it's not shown in the Parts Breakdown (at all).

    I personally would stick with the original recommendations for this particular engine.


    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

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    #8
    Don,

    How does the needle move up and down if there is no clip attaching it to the float tang?

    Edit, After thinking about it:
    I suppose the gas pressure/flow pushes the needle up and the float pushes it down when the bowl is full?
    Last edited by greauxpete; 11-29-2022 at 05:00 AM.

  9. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #9


    Somewhere along the line it was determined that multiple applications could be covered by the same needle (just that some did not require the spring).


    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

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    #10
    Had an issue with the top carb accelerator pump not spraying fuel. I determined the circuit between the bottom of the accelerator pump cavity and the "check ball" was not open. The white plastic ball was stuck in the seat, so I had to remove the small aluminum "tang", the spring, and eventually, gently nudged the plastic ball out (all using a couple of dental picks). I flushed the passage out with power tune and I am able to force air through the circuit now. Will remount the carb tommorow and test the accelerator pump for a spray pattern.

    Screenshot_20221129_213544_Samsung Notes.png

    Thanks again for your help Don.
    Last edited by greauxpete; 11-30-2022 at 07:15 AM.

  11. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #11
    Good catch!


    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

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    #12
    Quote Originally Posted by greauxpete View Post
    Had an issue with the top carb accelerator pump not spraying fuel. I determined the circuit between the bottom of the accelerator pump cavity and the "check ball" was not open. The white plastic ball was stuck in the seat, so I had to remove the small aluminum "tang", the spring, and eventually, gently nudged the plastic ball out (all using a couple of dental picks). I flushed the passage out with power tune and I am able to force air through the circuit now. Will remount the carb tommorow and test the accelerator pump for a spray pattern.

    Screenshot_20221129_213544_Samsung Notes.png

    Thanks again for your help Don.
    now you know why later carbs have no pump , as much as boats set up this was a problem for ethanol swelling that check ball
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #13
    After running on the stand at idle for 10-15 minutes,
    I noticed a slight leakage at the top of the accelerator pumps at the "plunger" seal.
    Not horrible but there is a leak.

    It looks like the seal is not sold separately and is part of the cap assembly and the cap assembly is NLA (didn't see any vendors who might have old stock).
    Is there a make shift seal or o-ring to remedy this?

    Thanks!

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    #14
    could be part of rebuild kit , also may swell as it is in contact with fuel
    .................................................. ...the scariest thing in life is the unknown ...................................

  15. Member
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    #15
    Regarding the same motor on this thread Mercury 150 HP.
    Serial number: 0D050150

    I am having a couple of minor problems:

    1. Extreme smoke at startup. Blue/grey almost white smoke. It seems excessive. My 2 stroke carbed 200s don't smoke like this motor at startup. Smoke is reduced after warm-up. Compression on this motor is 115-120 PSI across all 6. Thoughts on Diagnostics?

    2. Hard hot starting (after motor has sat for more than 5 minutes). Requires some throttle be applied.

    Does anyone have the jetting table for this carburetor? The carburetor is stamped WMH 7-1A, WMH 7-2A, WMH 7-3A.
    I want to make sure the jets are as per factory specs. My factory service manual only lists a WMH 7-1 (no "A" suffix).

    Screenshot_20231206_195805_Adobe Acrobat.jpg

    Screenshot_20231206_195835_Gallery.jpg

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    #16
    excessive smoke: if you can't see it flooding, than it may be that ck valve your fighting with.
    careful with the main jets the #5 may be different.

  17. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #17
    Need to check the oil injection system check valves- make sure the mixing check valve is intact/functioning, and make sure the crankcase pressure check valve is relieving all pressure from the remote tank within 5 minutes of engine shutdown.

    If either is not functioning right, you could end up with excessive amounts of OIL in the fuel right at the carbs.


    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

  18. Member
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    #18
    ^^^^^^ + 1
    .................................................. ...the scariest thing in life is the unknown ...................................

  19. Member
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    #19
    Quote Originally Posted by JOE54 View Post
    ^^^^^^ + 1
    Joe’s Back! How was the hunting?
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  20. Member
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    #20
    well im still goin some have seen a lot of deer just not the ONE yet ,been very warm lots of bugs snakes hogs coyotes trespassers. this year ive pretty much dedicated to my wifes hunting and getting her back in the woods since her liver transplant MAY 24 -2022 i came so very close to not having her with me , she got a doe TUESDAY with her crossbow so shes alot happier now , been fun its not all about the killn , im blessed , bowhunting is just different you get to see alot more than you could shoot at , so ill be around here thanks for asking.
    .................................................. ...the scariest thing in life is the unknown ...................................

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