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  1. 08-13-2018, 04:50 AM #1
    hookahawg
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    2002 Pro XB morning sneeze

    OT430697.

    Hello guys, my engine runs great, it's just that most initial morning start-ups, I'm getting a few "puffs" or sneezes.
    It never happens on the muffs and it never happens in neutral on the water. It only happens once I shift into gear and start to idle along for warm-up.
    If I press the pedal after warm-up, just a bit to sort of punch it, the sneeze goes away and will not happen for the rest of the day.
    I'm wondering if I need to take the fuel system apart again and clean some crud out? I did that a couple years ago and it was bad, the engine wouldn't even spool up there was so
    much crap in the system. I thought about reeds, but if it were a reed issue, wouldn't it sneeze or miss all the time?
    Anyway, any thoughts would be appreciated.
    Thanks as always.
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  2. Gamblinman
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    #2 08-13-2018, 05:38 AM
    Check your TPS setting. May need to bring it up a bit, even if it brings it out of factory spec. That lean sneeze is hard on reeds.
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."
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  3. hookahawg
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    #3 08-13-2018, 07:39 AM
    Woah....how does a halfwit like me do that? Thanks
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  4. EuropeanAM
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    #4 08-13-2018, 05:15 PM
    Good idea to start at the basics- beginning with a careful VISUAL inspection (look for broken or damaged BLEED lines too).

    Agree- checking the TPS setting, and verifying temp sensor readings are actually "reflective" of a cold engine's ambient temp would be good items to check also.

    TPS adjustment steps are covered in the Mercury Service Manual.


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  5. hookahawg
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    #5 08-13-2018, 06:35 PM
    Thanks Don. As I said it's only in the morning at first start up. Incidently, I just started and ran it on the muffs for 10 minutes. I DID NOT pump the primer bulb so it took three turnovers for it to fire up. Ran it through the gears, at idle, and not one miss or sneeze. Yesterday at the lake, I pumped bulb firm and had a short session of sneezing but only once I put it in gear and idled around before goosing it, at which point, sneeze stopped for the rest of the day....as it does everytime it starts the daywith a sneeze. Doesn't always sneeze either....weird.....
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  6. EuropeanAM
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    #6 08-14-2018, 09:29 AM
    Definitely get this checked- those "sneezes" are letting you know something is likely too lean at idle.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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