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  1. #1

    Default Mechanics, bah!at

    Have felt for a while the throttle on one engine was not opening all the way.
    My mechanic said he checked it, and it is!
    Well SeaHawk man convinced me to order a shop Manuel for the 250, and according to section 3-11 the spec for the "open" side of the theottle body should be 10mm, mine is 9.5mm, also, the throttle body cam is not rotated as much as the center engine is.
    Mechanic says that wont affect anything as the throttle body does no control the amount of fuel the engine gets.
    that is theoretically true, but The more air the engine gets, the more fuel it will need so IMHO it could be costing be some RPMs
    Thoughts?

  2. #2
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
    Posts
    3,736

    Default Re: Mechanics, bah!at

    Can't say about the 250, but on the 225 the throttle cam and throttle settings are critical for good performance. My 225 manual gives a very good description of how to adjust them in the "maintenance" section. That's Chapter 3 in my manual.
    CHawk 25 DLX

  3. #3
    Join Date
    Nov 2009
    Location
    temecula, ca., usa
    Posts
    2,678

    Default Re: Mechanics, bah!at

    The throttle body blade angle IS critical on ALL multi port FI engines. So much so that just a minute amount of dirt or grime will affect engine performance. A mis-adjusted blade is BOUND to be costing you horsepower in my opinion.

  4. #4

    Default Re: Mechanics, bah!at

    Exactly my thoughts, its the air flow that tells the engine management system how much fuel is needed to achieve the programmed air fuel ratio, not the other way around.
    I am an old hot rod guy, and one of the things was a bigger throttle body for more air flow when you made other changes (cams, heads exhaust) so you could fine tune the A/F ratio. Cant see that it would be any different on an outboard, even more critical IMHO being as they generally operate at higher RPMs.

  5. #5
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
    Posts
    3,736

    Default Re: Mechanics, bah!at

    Maybe a different mechanic is called for.
    CHawk 25 DLX

  6. #6

    Default Re: Mechanics, bah!at

    Unfortunatly not an option, he is the Honda dealers guy, also they are theMerc dealer.
    And, having a three year warranty kinda forces me to stick with him, finally he is the best we got, and CAN be relied on in emegerency issues.

  7. #7
    Join Date
    Mar 2009
    Location
    Cincinnati, OH USA
    Posts
    4,176

    Default Re: Mechanics, bah!at

    Not only is the throttle body controlling air flow, the throttle position sensor moves with the opening of the throat.

    The throttle position sensor tells the engine that you want more speed.

    Mike

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