power problems

Discussion in 'Gas Engines' started by stevenf12, Jul 29, 2012.

  1. stevenf12
    Joined: Jul 2012
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    Location: alaska

    stevenf12 New Member

    I have an 87 4.3l omc my problem is when i give it trottle at low rpms it will die and then when i work around that it will sometimes bogg down trying to get up on step and when i do get it up on step running 3200 rpm it sometimes starts to lose power and bogg down to around 2500 rpm any ideas
     
  2. 7228sedan
    Joined: Nov 2009
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    Location: New Jersey USA

    7228sedan Senior Member

    I'd suspect water in the fuel or a carb problem to start with. Does the motor rev up clean in neutral?
     
  3. stevenf12
    Joined: Jul 2012
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    stevenf12 New Member

    Yes motor revs fine in neutral and forgot to say there is a weak and sometimes strong oder of fuel when up and running
     
  4. 7228sedan
    Joined: Nov 2009
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    7228sedan Senior Member

    I suspect a carb problem, either a faulty gasket causing fuel to leak and cause a severely rich condition. I would pull the carb off and put a rebuild kit into it. Set all to factory specs and go from there. Specifically the needle, seat and float settings Is there any evidence of fuel on the motor after you run it? On top of the intake manifold for example?
     
  5. stevenf12
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    stevenf12 New Member

    as afact i did notice some on the manifold and thank you ill try the rebuild kit this week.
     
  6. 7228sedan
    Joined: Nov 2009
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    7228sedan Senior Member

    I had a very similar problem with my motor last year. Make sure you replace the float too. They do not come with all of the rebuild kits. Good Luck!
     
  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    You only need to replace the float if there's a problem, such as a leak in it or a broken needle tab, etc. Floats rarely good bad, though eventually they do.
     
  8. 7228sedan
    Joined: Nov 2009
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    7228sedan Senior Member

    Very true PAR however I would hate for him to put it all back together with the old float only to find that there is a pin hole. They are cheap enough and should be replaced in a 25 year old carb with an unknown history ;-)
     
  9. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I have a 50 year old carb with it's original float. It's an easy thing to check as well.
     

  10. 7228sedan
    Joined: Nov 2009
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    Location: New Jersey USA

    7228sedan Senior Member

    Sure, and you can even solder the old brass floats too, but for $6.79 why not change it?
     
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