Results 1 to 5 of 5
  1. #1
    Member
    Join Date
    Feb 2008
    Location
    Hazard Kentucky
    Posts
    1,942

    number 5 plug not firing

    My 200 pro xs 4s had a rough idle and hesitation upon full throttle and surging at speed. Took to my dealer. Said plug 5 not firing. They changed all the plugs and wires under warranty. What would cause this plug to go bad and not fire?
    2b733274.

  2. Member
    Join Date
    Apr 2014
    Location
    SW, Ohio
    Posts
    17,427
    #2
    seems to happen a lot about 40 plus hours and normal as of now??
    2022 z519 cup 225 merc 4s ser # 3B210484. 2--hds12 live units. 2 poles, atlas plate, ghost, hamby's, active target, merc digital gauges
    2002 basscat pantera 3 (dad bought new) sold 8-2-22
    2000 stratos 20 ss (bought new) 200 hp Rude ficht great boat/motor sold 11-21
    pulled by a 2500HD Denali
    proud dad of an ARMY Captain
    MAGA
    ASE/GM Master tech before tools

  3. Member
    Join Date
    Feb 2008
    Location
    Hazard Kentucky
    Posts
    1,942
    #3
    I think mine has around 55 hours. So that seems about right.

  4. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    95,217
    #4
    Depends not only on HOURS, but also on how it was run DURING those hours.

    Engines that see a lot of runtime in 1800 RPM and below category are far more likely to require spark plug replacements.

    At 2.5 years of use, it's not that out of the ordinary to have to replace the plugs.


    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

  5. Member
    Join Date
    Feb 2008
    Location
    Hazard Kentucky
    Posts
    1,942
    #5
    I fish a small lake alot. So it does see alot of idle and short slower runs. May need to open it up more.