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Suddenly slow to start?

Discussion in 'Early CJ5 and CJ6 Tech' started by StraightToPlaid, Apr 25, 2007.

  1. Apr 25, 2007
    StraightToPlaid

    StraightToPlaid Ludicrous speed!!!!

    West Chester, OH
    Joined:
    Nov 21, 2006
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    338
    My CJ always started right up with just a little bit of the choke. Suddenly it's taking almost a minute of cranking to fire, but as soon as it fires it catches quickly and runs normally. Am I looking at a fuel pump issue?

    Also, did these originally come with a mechanical or electric fuel pump? I can turn the key to run but not start it and hear a fuel pump on the rear tank start whirring.
     
    StraightToPlaid, Apr 25, 2007
    #1
  2. Apr 25, 2007
    mb82

    mb82 I feel great!

    Charlottesville Va
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    Mar 17, 2003
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    2,706
    Sounds to me like your carb is draining back into your fueltank.
     
    mb82, Apr 25, 2007
    #2
  3. Apr 25, 2007
    StraightToPlaid

    StraightToPlaid Ludicrous speed!!!!

    West Chester, OH
    Joined:
    Nov 21, 2006
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    338
    Is this an issue or is it just annoying?
     
    StraightToPlaid, Apr 25, 2007
    #3
  4. Apr 26, 2007
    mb82

    mb82 I feel great!

    Charlottesville Va
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    A check valve has gone bad. More of an annoyance then anything.
     
    mb82, Apr 26, 2007
    #4
  5. Apr 26, 2007
    dohc281

    dohc281 It is what it is.

    Laurel Springs, N.J.
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    Dec 30, 2004
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    They had check valves in 1971?
     
    dohc281, Apr 26, 2007
    #5
  6. Apr 26, 2007
    mb82

    mb82 I feel great!

    Charlottesville Va
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    I thought there was one in the carb?
     
    mb82, Apr 26, 2007
    #6
  7. Apr 26, 2007
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Sep 21, 2002
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    Not sure about the check valve issue but there should be enough gas in the carb for it to start. I don't know that much about electric pumps but if the pump is running obviously it's pumping gas which definitely sounds like a leakdown somewhere. Sounds like someone added an electric fuel pump, I wouldn't think it would be stock in '71.
     
    Glenn, Apr 26, 2007
    #7
  8. Apr 26, 2007
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    With the Solex after a few days the carb needs to be refilled, so it needs to turn over a bit. They say it's due to evaporation since the fuel bowl is small. I never thought much about it. Is it possible for fuel to be sucked back out of the carb? I guess if nothing was stopping it maybe the vapors could be sucked back in to a fuel tank that wasn't vented.
     
    Glenn, Apr 26, 2007
    #8
  9. Apr 26, 2007
    StraightToPlaid

    StraightToPlaid Ludicrous speed!!!!

    West Chester, OH
    Joined:
    Nov 21, 2006
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    338
    There's no leak that I can find, no smell of gas or gas on the ground. Right now the CJ is my daily driver so its not sitting long enough for the gas to evaporate out of the bowl.

    The carb does look newer then the rest of the engine. It's possible that the PO replaced that too.
     
    StraightToPlaid, Apr 26, 2007
    #9
  10. Apr 26, 2007
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
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    No check valves in the carburetor.

    Fuel pump should be mechanical to be stock.

    I can't imagine how gas would siphon back into the tank.

    Evaporation from float bowl is my best guess. Have temperatures recently increased in your area?
     
    sparky, Apr 26, 2007
    #10
  11. Apr 26, 2007
    1960willyscj5

    1960willyscj5 Well-Known Member

    Mesa, Arizona
    Joined:
    Nov 27, 2006
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    2,793
    In the last week we have gone from mid 60's to the mid 80's.
    Rained on Friday and the barometer dropped to the 29.5 mark.
    Rained again on Monday. Barometer now is at 29.85, yesterday it was at 30.

    It's been fluxuating a lot the last couple of weeks. Usually it stays a couple of ticks off of the 30 mark. fairly steady. Temps are supposed to go to almost 100 by Saturday. Humidity has been pretty high for this time of year. (that might effect the carb some.)Tempe and Phoenix are basically on opposite sides of the Salt River and the Sky Harbour Airport (which is where most of the readings come from. I have my own gauges.)

    One thing to check that might be causing it is your aircleaner element. If it has suddenly decided to clog, that will make the initial start longer.:) :coffee: :hurrican:
     
    1960willyscj5, Apr 26, 2007
    #11
  12. Apr 26, 2007
    StraightToPlaid

    StraightToPlaid Ludicrous speed!!!!

    West Chester, OH
    Joined:
    Nov 21, 2006
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    338
    And I just happen to have a brand new air cleaner lying around here somewhere too.

    I just remembered that I have seen a little bit of fluid below my jeep in the past week, but figured it was oil (I've got too used to that leaking :oops: ) I did think it odd that it wasn't there later but figured the crappy asphalt in front of my house just soaked it up. Where on the carb should I look for a leak that would drain my bowl?
     
    StraightToPlaid, Apr 26, 2007
    #12
  13. Apr 26, 2007
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
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    It'd have to be the bottom of the bowl, the inlet is on the top.

    I don't see how it would leak out of the carburetor unless it was just plain cracked?
     
    sparky, Apr 26, 2007
    #13
  14. Apr 26, 2007
    StraightToPlaid

    StraightToPlaid Ludicrous speed!!!!

    West Chester, OH
    Joined:
    Nov 21, 2006
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    338
    I really hope not, I don't have cash for a new one.
     
    StraightToPlaid, Apr 26, 2007
    #14
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