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  1. #1

    Question Carter AFB fuel problems

    Hi all. I have a 61 389 ,with a 4 bbl Carter AFB factory fitted , the problem i have is that when i park the car with a hot engine , over nite , the car will not start the next morning until it is cranked & cranked & cranked until the fuel is fills the fuel bowl(or i tip fuel down the carb ) , in other words the fuel goes somewhere ???? car starts very well all other times . Is the fuel evaporating out of a breather in the carb overnite ??? I have replaced the carb with a reconditioned carb and it still does the same thing . Do i need to fit an electric fuel pump ??? These cars would not have had this problem from new so there must an answer ,,
    Thanks in advance for your help ,,, Kel.

  2. #2
    TININDN Guest

    Default

    I think it's todays fuel. I have the same issue with my older Pontiacs, but they generally start pretty good after standing overnight, it's after sitting a few days or a week that I have to crank and pump the gas pedal to get them to fire.

    The fuel appears to be more volatile today versus decades ago, and it doesn't seem to get that varnish smell after sitting over the winter. If someone blindfolded me and took me to an old car boneyard my nose would tell me where I was by that gasoline varnish aroma.

  3. #3

    Question

    Hi .. I do not think it is the fuel Quality , all the fuel goes out of the carb over nite . there are no leaks . i have 2 other Pontiacs ,one has a holly & the other has a Rochester Quadrajet, and they do not have the problem . , thanks kel.

  4. #4
    TININDN Guest

    Default

    Kel -

    Do you think the fuel is leaking from the carb internally into the intake manifold? Have you ever removed the carb the next morning before trying to start to see if their is raw fuel "puddled" in the intake manifold? Or, opened the throttle and looked down into the intake with a flashlight?

  5. #5

    Default

    Quote Originally Posted by TININDN View Post
    Do you think the fuel is leaking from the carb internally into the intake manifold? Have you ever removed the carb the next morning before trying to start to see if their is raw fuel "puddled" in the intake manifold? Or, opened the throttle and looked down into the intake with a flashlight?
    I also wonder if this may be the problem.

    Todd Crews
    POCI 1957 Technical Advisor

  6. #6
    Join Date
    Nov 2008
    Location
    Suburban Philadelphia Area
    Posts
    43

    Default

    When my car sits idle for 4 or 5 days,I experience the same problem, and there are no leaks....just some evaporation, I believe. The way I remidy the issue is to remove the air cleaner, then squirt gas in the 4 tubes that I believe feeds the bowl. The results have been great. I bought a plastic bottle that has a long thin metal spout or tube at Harbor Freight that I fill and keep handy to use whenever I the car sits.. Maybe one of those plastic mustard/ketchup squirt bottles would also serve the purpose.

    I noticed that the gas that I have in the bottle tends to evaporate even those it is closed tightly...I guess that is what is happening in the carb.

    Vince
    Last edited by VJCarbone; December 15th, 2011 at 11:26.

  7. #7
    Join Date
    Nov 2008
    Location
    Villa Rica GA
    Posts
    51

    Default

    For a cold start, have you checked to see that your choke is setting when you press the accelerator to the floor once? I have reworked many of the Carter carbs and have never had the problem you describe. The AFB carb is not prone to loosing fuel into the intake, unlike the Rochester quads. The only way an AFB would do that is if it has a cracked base and since you have installed a second carb with the same (apparent) problem, a cracked base is probably not the case. So, back to the choke setting. Also, a word of caution about using a plastic bottle for a 'spritzer', some plastics don't like gasoline so be very careful with that idea of spraying gas into the carb to prime it. Better to find the real problem. Back siphoning gas from the carb though the fuel line/fuel pump is also very unlikely due to the float needle/seat in the carb and the check valve in the fuel pump. An electric puel pump installed so that it is pushing from the fuel tank would likely be a good bandaid, but that will simply mask the problem and could create another one - flooding - since it runs all the time ignition is on. You could set up the electrical operation so that you control the pump with a toggle switch and only supply voltage to run the pump just for cold starts and once the car is running turn off the power to the pump.

    That's my $.02 for what it's worth. Keep looking for the real problem and that's the best solution.

    Frank

  8. #8
    Join Date
    Oct 2008
    Location
    Sour Lake, Texas
    Posts
    28

    Default

    As Frank said there is no way for an AFB to lose fuel unless the base is cracked or something like that. AFB bowls are just that, bowls, and unless the carb is turned upside down or the bowl is comprimised fuel cannot just escape.
    It also cannot drain back down through the fuel pump because the needles and seats are in the bottom side of the top and thus cannot drain back down through the line to the fuel pump.

    I have experienced what you are experiencing although never in one night. I think the ethanol laced fuel does evaporate out of the carburetor bowls, AFBs and tripower two barrels both, much more rapidly than the old stuff, and for that reason I have installed electric fuel pumps on my cars that push through the mechanical pump. When I get in the car I turn the key on and let the electric fuel pump refill the bowl (bowls on a tripower) until the sound of the electric pump changes, then pump the gas pedal four or five times, and the car starts right up.

    I don't know what your problem is but you might put a multimeter on the coil windings and see if it has started to corrode internally and isn't putting out like it should. I've also had hard starting problems and a weak coil was the problem.

  9. #9

    Default

    Hi All , thanks for your ideas and help . i think i will install an electric pump back near the tank . on a switch , to turn on and help with starting after being hot parked overnite . i live in the northern tropics of Australia ,the weather is similar to Florida's summer, maybe the extra heat has a bit to do with the problem .. thanks again ,, Kel. see you at St Charles in july .

    RIP David Bennett

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