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  1. #1

    Idle Question 150 ProSX

    2B651441
    30 ish hours maybe
    2019

    Been a while noticing when motor is 800 rpm idle
    there is a noticeable steady miss. Going in forward I can feel it.
    If I give it more gas, just 1000 rpms it’s smooth as silk.
    If it only happened in forward I know prop clatter which I have too.
    Something to worry about?
    Runs like crazy good, 59.8 (gps) 6100 rpms (analog)

  2. Member
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    #2
    My 150 ProXS does the same. It idles rough at times but is smooth at fast idle and beyond. I think that the 3 cylinders may have something to do with it at idle speed.
    2008 Triton TR200 - Merc 250 ProXS - Humminbird 1197 & 1198 - Dual power poles

  3. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #3
    Quote Originally Posted by BR374 View Post
    2B651441
    30 ish hours maybe
    2019

    Been a while noticing when motor is 800 rpm idle
    there is a noticeable steady miss. Going in forward I can feel it.
    If I give it more gas, just 1000 rpms it’s smooth as silk.
    If it only happened in forward I know prop clatter which I have too.
    Something to worry about?
    Runs like crazy good, 59.8 (gps) 6100 rpms (analog)
    Engine IDLE is not 800 RPM's. Idle is PCM controlled, usually in the 550-630 range. If you are applying throttle (any), that is no longer "idle".

    A when operating at just barely touching the throttle (such as 800 RPM's) it would not be uncommon to feel some rough running, as this is an area that the engine normally would not run in. As for "prop clatter"- good idea to check to make sure your prop is properly torqued (and which hub you have). Flo-Torq IV or SSR Hub Kit would be best.

    Quote Originally Posted by jimham82
    I think that the 3 cylinders may have something to do with it at idle speed.
    Better check with your dealer and find out what happened to the 4th cylinder.


    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

  4. Member
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    #4
    Quote Originally Posted by EuropeanAM View Post
    Engine IDLE is not 800 RPM's. Idle is PCM controlled, usually in the 550-630 range. If you are applying throttle (any), that is no longer "idle".

    A when operating at just barely touching the throttle (such as 800 RPM's) it would not be uncommon to feel some rough running, as this is an area that the engine normally would not run in.
    FWIW, when I use my SC-1000 Troll Control, my 150 4s is smooth as silk from the minimum (550RPM, as I recall) all the way to the max (1000) RPM, never feel any roughness...

    Maybe I got lucky?

    Quote Originally Posted by EuropeanAM View Post
    As for "prop clatter"- good idea to check to make sure your prop is properly torqued (and which hub you have). Flo-Torq IV or SSR Hub Kit would be best.



    Better check with your dealer and find out what happened to the 4th cylinder.
    +1 My Prop Rattle (Clatter) got way better when using Flo-Torq IV
    2016 Ranger 1850 LS Reata / Merc 150 4s / SmartCraft / Lowrance HDS Carbon SS3D

  5. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #5
    Troll Control is a bit different than advancing the throttle on the 150 Fourstroke.


    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

  6. #6
    When I referred to idle at 800 rpm (maybe more like 750) I should have stated the motor is in neutral.
    While in neutral I feel a “Miss”. When I first crank it it seems fine. Then a few mins of neutral warm up it starts the Miss.
    Then put motor in forward I still feel it but goes away with a tiny touch of throttle.
    i was used to my previous 2 cycle 150 OMC vibrations.
    Maybe I just expected a smooth NO feel vibration with 4S.
    Regardless, I super happy and proud of my 150 PXS.
    Last edited by BR374; 12-11-2019 at 02:41 PM.

  7. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #7
    Perhaps it would be a good idea to get a local dealer to give it a listen/check, just to make sure there is nothing out of the ordinary.

    If it's truly idling in neutral at 700 (via Smartcraft... analog tachs are often inaccurate), that could be part of the problem.

    Where in SC are you located?


    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

  8. #8
    Aiken

  9. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #9
    If you’re ever going to be up this way, let me know.


    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

  10. #10
    PM sent

  11. #11
    PM sent

  12. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #12
    Thanks- see you this 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

  13. Banned
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    #13
    Not to derail, but my 75 has idled at 700 since day one.