69 472 Q-Jet not getting enought fuel
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500, 472, 425, 368 Discussion, 69 472 Q-Jet not getting enought fuel in Cadillac Engine Technical Discussion; Hey all - This is my first Cadillac, so sorry if the questions are simplistic... I have a 69 Fleetwood ...
  1. #1
    ammason is offline Cadillac Owners Member
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    69 472 Q-Jet not getting enought fuel

    Hey all - This is my first Cadillac, so sorry if the questions are simplistic...

    I have a 69 Fleetwood Limousine with a 472 and Q-Jet carb. The car was misfiring, and since it'd sat for 6 years before I got to it, I guessed the carb was clogged and it was running lean, so I pulled the carb, cleaned it, and threw in a new gasket/acc pump kit.

    Turns out plug wires 1 and 3 were switched - put those back and the thing runs great... For about 30 seconds, and then it drains the bowl and hobbles along on idle.

    The problem is that it's not getting enough gas into the bowl... I can pull the top off the carb, turn the engine over a few times and fill up the bowl, then put the top back on and it runs great for again, about 30 seconds. At this point opening the throttle, instead of making hte car roar, produces this sucking sound and sputters.

    I adjusted the float to 1/4" when I had it apart - I only replaced the plug portion of the needle valve as the kit came with a valve seat that was too tall. Perhaps there's some gasket material that's pushing down only when I clamp it together? I'll check that out tonight...

    The fuel filter isn't clogged - I'm actually running gas from another external tank and it wasn't an problem before I pulled the carb...

    Any ideas?

    Thanks!

    Aaron

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  3. #2
    jk1000 is offline Cadillac Owners Member
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    Re: 69 472 Q-Jet not getting enought fuel

    Check your fuel pressure, should be about 5-6 psi. You could have a carb problem, but you need to rule out any possible fuel delivery problem first.

  4. #3
    BluEyes's Avatar
    BluEyes is offline Cadillac Owners Enthusiast
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    Re: 69 472 Q-Jet not getting enought fuel

    Check that you've got the fuel filter in the carb properly installed and the float level set right.
    It doesn't have one of those sintered bronze filters does it?

  5. #4
    ammason is offline Cadillac Owners Member
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    Re: 69 472 Q-Jet not getting enought fuel

    Fuel delivery is fine - healthy flow and ok pressure coming in... Is there another fuel filter at the carb? The one in the tank was clean...

    I'm pretty sure it had something to do with me breaking off a piece of the float pivot mount in the bowl... $200 later I've ordered an edlelbrock 1411 so hopefully that will solve things... We're taking the beast across the country and $200, if it solves this and future break-down issues, will be well worth it...

    Thanks for all the help!

    Aaron

  6. #5
    davesdeville's Avatar
    davesdeville is offline Banned
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    Re: 69 472 Q-Jet not getting enought fuel

    There's a fuel filter right where the fuel line enters the carb. Hard to miss.

  7. #6
    BOODER is offline Cadillac Owners Member
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    Re: 69 472 Q-Jet not getting enought fuel

    There Is Also A Fuel Filter Down At The Fuel Pump. Let Us Know How You Fixit. Don

  8. #7
    jk1000 is offline Cadillac Owners Member
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    Re: 69 472 Q-Jet not getting enought fuel

    If fuel pressure/delivery is good and the inlet filter is good (as mentioned in previous post) then your trouble is in the carb. I cannot remember if 69 used a bronze inlet filter or a screen like they did a few years later. A bronze filter can clog and look fine.
    I think your problem is with the Float, needle valve and seat. Find the correct new parts and make sure everything is assembled and adjusted properly. This is CRITICAL.

    Good luck, keep us posted.

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