Thread: 99 225 EFI

Results 1 to 9 of 9
  1. #1
    Member Jay's Avatar
    Join Date
    Jul 2004
    Location
    Mocksville, NC
    Posts
    382

    99 225 EFI

    Been bored out .030 currently running the champion QL77C plugs but seems to foul up some on long idles in no wake zones, is there a warmer running plug I can use to prevent this?

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    97,931
    #2
    QL77CC is the ONLY Factory Recommended plug for this engine.

    Are you still running oil injection?

    Injectors flow-tested and calibrated?

    TPS setting currently?

    What temp is the engine reaching (test each side, on thermostat cover, with a hand-held infrared temp gun)?


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  3. Member Jay's Avatar
    Join Date
    Jul 2004
    Location
    Mocksville, NC
    Posts
    382
    #3
    Quote Originally Posted by EuropeanAM View Post
    QL77CC is the ONLY Factory Recommended plug for this engine.

    Are you still running oil injection? Yes

    Injectors flow-tested and calibrated? No idea

    TPS setting currently? No idea

    What temp is the engine reaching (test each side, on thermostat cover, with a hand-held infrared temp gun)?
    Have access too a temp gun, where exactly do you take the temp reading?

    the TSP setting I have no idea how to Check that. Is there a link to a how too for it anywhere?

    injectors calibrated? They were all replaced when overhauled bit that still doesn't mean a whole lot...

    I was just think the next hotter running plug may cure it.... Old school thinking I guess.....

  4. Major Flagelator Gamblinman's Avatar
    Join Date
    Jun 2004
    Location
    Yantis, TX
    Posts
    4,121
    #4
    Not any warmer, but you can try the NGK Iridium plugs. I would definitely check all the items on Don's list first and make sure they are correct, just to ensure. Gman
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."

  5. Member Jay's Avatar
    Join Date
    Jul 2004
    Location
    Mocksville, NC
    Posts
    382
    #5
    Will do, I appreciate all the input gentlemen....

  6. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    97,931
    #6
    Quote Originally Posted by Jay View Post
    Have access too a temp gun, where exactly do you take the temp reading?

    the TSP setting I have no idea how to Check that. Is there a link to a how too for it anywhere?

    injectors calibrated? They were all replaced when overhauled bit that still doesn't mean a whole lot...

    I was just think the next hotter running plug may cure it.... Old school thinking I guess.....
    Temp: Aim it right in the center of the thermostat covers (at the top of each cylinder head) for best results.

    TPS: Should be set at .95-.98 VDC (and setting proceedures are covered in the OEM Mercury Repair Manual). A TPS test harness is recommended for this proceedure.

    Injectors: "Replaced" is pretty relative.... were they new, used, or ???

    Plugs: Don't arbitrarily start changing plugs or heat ranges- results aren't always good for the engine. Stick with the plugs DESIGNED for the engine for best/safest results.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  7. Member Jay's Avatar
    Join Date
    Jul 2004
    Location
    Mocksville, NC
    Posts
    382
    #7
    Quote Originally Posted by EuropeanAM View Post
    Temp: Aim it right in the center of the thermostat covers (at the top of each cylinder head) for best results.

    TPS: Should be set at .95-.98 VDC (and setting proceedures are covered in the OEM Mercury Repair Manual). A TPS test harness is recommended for this proceedure.

    Injectors: "Replaced" is pretty relative.... were they new, used, or ???

    Plugs: Don't arbitrarily start changing plugs or heat ranges- results aren't always good for the engine. Stick with the plugs DESIGNED for the engine for best/safest results.
    Injectors were new, and I wouldn't have changed to a different plug without verifying it first lol... Thanks again....

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    97,931
    #8
    Good... be sure to report back when you get the other items checked.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  9. Member Jay's Avatar
    Join Date
    Jul 2004
    Location
    Mocksville, NC
    Posts
    382
    #9
    Quote Originally Posted by EuropeanAM View Post
    Good... be sure to report back when you get the other items checked.
    Will do.....