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  1. #1
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    Optimax 150 rough idle

    1B287307 06 150 optimax 339 hours
    rough idle. Seems worse in gear when in the water. It has new plugs and wires, I’ve performed a power drop and can’t see a obvious change on any cylinder. Removed and inspected tracker valve, pressure regulator and pulse pump diaphragms, they all look good. I’ve verified fuel to air pressures to be 90-80as it should be. Any thoughts as what to look at next?

  2. Member
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    #2
    My thought always goes to broken reeds with a rough idle as one possibility.
    Mercury 2002 200hp Carbed Saltwater
    OT566776
    2002 Cape Horn 22' Bay

  3. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #3
    I concur. Very common on the 2.5L models... and sometimes may not even be broken (just "grit" in them holding them open). Make sure the inside of the lower cowling, and the adapter plate are kept "eat off them clean" as this is often the area where grit resides inside the cowling (until it's sucked into the 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).
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    #4
    Thanks for the replies. I will check them out.

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    #5
    Order a set of TDR reeds from Don and rid your engine of potential critical failure from ingesting a piece or pieces of the SS reeds. Upgraded mine 5yrs ago and glad I did.
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax


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    #6
    Can the reed petals be upgraded without lapping or replacing the cages? Should they be replaced with assemblies?

  7. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #7
    Without replacing cages: Yes, as long as they are in good condition.

    Without lapping: NO (they will not seal properly unless they are done correctly).


    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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    #8
    is it
    Last edited by bobco; 04-07-2020 at 05:32 PM.

  9. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #9
    It is possible, but since the reeds are the last device inline before the crankcase (between oil delivery ports and crankcase) it is very wise to perform an oil pump prime sequence (regardless).


    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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    #10
    on
    Last edited by bobco; 04-07-2020 at 05:31 PM.

  11. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #11
    Quote Originally Posted by bobco View Post
    on an optimax I dont see any oil lines delivery points in front of reeds? 6 ports off oil pump to 6 cyclinders and 1 port to compressor. Just a real pain out here in the sticks to get someone with a computer. would rather not disconnect all the oil lines from pump it I can work around it.
    For this 2.5L model, you are correct. The oil is delivered into the runner between the crankcase and intake port (rather than at the reed plate as occurs with the 3L models). Sorry about that confusion.

    This does, however, make it particularly challenging to remove the air handler WITHOUT disconnecting oil lines.


    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