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  1. #1
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    115 optimax operating temp range?

    Hi all,
    My mercury optimax is operating between 140 - 150 degrees. At idle around 140, mid range speed 145, and WOT 150. Water temp is 65 degrees. Is this normal? I read so many posts about much lower temps. The motor is a 2006 115 hp. Serial # 1B372539. The reading are from the smartcraft guage.

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #2
    That is within acceptable parameters, although I would normally expect the WOT temps to drop.

    Always start at the SOURCE: The Water Pump.


    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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    #3
    There is a new water pump installed. Water pressure is 4.5 at idle and then rises as RPM's are increased. AT WOT the pressure is around 24 PSI. At 3650 RPM, 17 PSI. Is this OK?

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    #4
    Those are good numbers, specs are at idle and WOT only anything in between is what it will be. Should see minimum 1 - 3psi at idle and 12+ @ WOT (the 1.5L may be 15+ @ WOT Don or Joe54 can confirm). Pressures will be higher with a newly serviced water pump and should settle after a few hours run time.
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  5. Member sorrybasser's Avatar
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    #5
    Sounds like the poppet valve is stuck closed. Don't forget to clean the strainer.

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    #6
    Quote Originally Posted by SilverFox579 View Post
    Those are good numbers, specs are at idle and WOT only anything in between is what it will be. Should see minimum 1 - 3psi at idle and 12+ @ WOT (the 1.5L may be 15+ @ WOT Don or Joe54 can confirm). Pressures will be higher with a newly serviced water pump and should settle after a few hours run time.
    +1 ^^^^^^
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #7
    What is the temperature that would set off the overheat alarm? Can't seem to find that anywhere.

  8. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #8
    By "Overheat Alarm" do you actually mean a SOLID TONE Warning (which is simply a CRITICIAL WARNING, indicating a serious condition exists and you should shut the engine down as soon as safely possible)? There are a number of items that can cause this warning.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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    #9
    Yes, I know on my 200 hp carb 2-stroke it is 210 degrees. Can't seem to find that anywhere for the 115 optimax.

  10. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #10
    Quote Originally Posted by Peetee907 View Post
    Yes, I know on my 200 hp carb 2-stroke it is 210 degrees. Can't seem to find that anywhere for the 115 optimax.
    Well, technically 194 degrees but that's close enough.

    The Optimax will trigger well before that, as the PCM has progressive logic programmed (and utilizes only the Critical Warning, Non-Critical Warning, and ENGINE GUARDIAN to attempt to protect the engine).

    Exact temperature is part of the PCM Calibration data, which we're not privy to. In general, somewhere in the 170 degree range would be where you should expect warnings.

    You can also have engine temps in the 130 degree range and STILL get a CRITICAL FAULT Warning (Solid Tone). One common example is an AIR COMPRESSOR overheat (strainer clogged, telltale fitting clogged, etc).


    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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    #11
    Thanks for the info. I guess I am used to the old technology. Still learning about the Optimax.

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    #12
    the one ive seen at idle in shop on CDS went off at 176
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #13
    Reviving this thread. Had "one second beep" alarm go off at 165 degrees. Throttled down to idle and temps immediately dropped. Clean out poppet valve. Now between 3000 and 4200 RPM's temp is at 149 degrees (14.5 - 15.5 PSI water pressure). AT 2000 RPM's 145. At idle 143 which is expected. At 4400 RPM's water pressure drops and temp goes down to 115 degrees (12.5PSI pressure). Question is why doesn't temp drop at midrange operation? Could the spring be too stiff? I am used to temps dropping at 2000 RPM's on a carb 2-stroke. Any advice is much appreciated!

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    #14
    possibly could
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #15
    Thanks Joe. Do you know what the part numbr would be for the lighter spring (if that even exists)? manual states part # 892321. Is there another part I could try or any suggestions?

  16. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #16
    There is one spring (only) for the poppet on that engine, as specified in the Parts Catalog.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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    #17
    Thought I would close out this thread. Got a new spring. Compared it to what was installed when I bought the motor. They were not the same! Recommended spring was shorter and much lighter! Motor runs alot cooler now at all RPM's! At 3600, it will cool down to 118 degress where as before it would run at 149! Thanks all for your help with this.

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    #18
    sounds like somebody messed with it
    .................................................. ...the scariest thing in life is the unknown ...................................

  19. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #19


    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