Hard starting

Discussion in 'Troubleshooting & Diagnosis' started by Howard Buckner, Aug 14, 2021.

  1. Howard Buckner

    Howard Buckner Member

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    I have a 71 402 that is completely stock. Have had the carburetor rebuilt and the car runs well. If i don't use the car for a day, when i go to start it, i have to physically pump the pedal at least ten times or more to get gas into the carb so it starts. This is after i depress the pedal to set the choke. Is this a symptom of the choke not being set up right or a leakdown in the carburator?
     
  2. xten

    xten Veteran Member

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    Sounds like the diaphragm in the fuel pump letting the fuel drain back. Mine did that
     
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  3. MChamp

    MChamp Veteran Member

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    yessir. 2nd diaphragm.
     
  4. Howard Buckner

    Howard Buckner Member

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    if that were the case, wouldn't i see fuel leaking from the weephole (if the pump has one)?
     
  5. tom3

    tom3 Veteran Member

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    Is this a quadrajet carb? Pull the air cleaner off and look for a shot of gas when you pump the pedal. Does the choke butterfly close?
     
  6. 73 Z

    73 Z Veteran Member Gold Member

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    Or Fuel in the oil, smell the oil dipstick. Does it run well at idle, and under load?
     
  7. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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  8. rocket dawg

    rocket dawg Veteran Member

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    I put the wrong fuel pump on and it drained back repeatedly. AC Delco pumps for me until recently. I went EFI.
     
  9. Vettenick

    Vettenick Vettenick

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    How old is that pump? One way to find out if it is drain back is to block off or pinch the fuel supply line after you gave run it. If after your time period, it starts immediately, then you know it's drain back.
     
  10. Howard Buckner

    Howard Buckner Member

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    great idea
     

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