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Originally Posted by Motorhead
I haven't used a Carter AFB but I had an Edelbrock Performer on my 460 for a few years. Initially it had a hot-start problem that was solved with the 'phenolic' (wood) spacer, but I've never ever had a carb evaporate completely dry after a matter of days. I could let the Bronco sit for a week and it would still fire on the first crank. My pickup normally sits for weeks at a time out in the direct sunlight and summer temps, and it's always fired right up, never had a problem with it evaporating off completely. Granted, it has an electric fuel pump, but I don't give it time to fill the carb, I just put the key in and crank.
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Yes, but what year is the truck and does it have EVAP? The hot start problem was fuel percolation, boiling of the fuel in the bowl due to heat soak after shutdown. If she boils, it has to evaporate somewhat. Again, it depends upon the design of the carb and if any EVAP systems are used.
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The needle and seat are located well above the floor of the fuel bowl on every carb I've ever worked on (Edelbrock, Holley, Quadrajet, motorcycle and other small engine carbs), making it impossible to drain the fuel bowls through the fuel inlet. You might be able to skim a little fuel off the top before the level gets down to the needle and seat, depending on the carb, but it would never be able to drain enough out to cause a no-start condition.
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True. But a AUTOLITE 4100 or HOLLEY 4010 will have the needle/seat on the bottom of the fuel bowl and draining through the needle/seat is possible, especially with a defective check valve in the pump. On an AFB, if the fuel level either boils or say the fuel level is set too low, it will leave the needle/seat open after shutdown leading to the
possibility of further evaporation. This will be compounded if the car is parked on a non-level surface.
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It could complete evaporation due to boiling like you're saying, but would have to happen before the engine cools off, because I still don't think 'normal' evaporation would drain the bowls in 3 days. In that case, if he waited anything more than a couple hours, he would have this condition.
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No, it would take a few days to evaporate completely and the pump would have lost it's initial prime, compounding the problem.
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A leak, on the other hand, could take any duration depending on the severity of the leak. You may not be able to see anything out of the ordinary immediately after shutoff, and as soon as you crack the throttle open the accelerator pump will squirt making it impossible to find a puddle from the leak. The only good way I know of to check for a leak is to take the carb off the vehicle with it full of fuel and set it on a box or something to watch for the wet spot/drips. I could be wrong, maybe my inexperience with the Carter AFB is showing through here, but I was under the impression that they were more or less identical to the Edelbrock Performer carbs.
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There would have to be a flaw in the casting (fuel bowl) to leak down at this rate. There is no plug at the bottom to leak as on a say ROCHESTER.
The EDELBROCK is the copy of the CARTER, manufactured by WEBER.
Take a small glass of oxygenated fuel and leave it outside for a few days and see what is left. Pump gas is now formulated for closed injection systems.
As for the leak itself, one would shine the light down the venturis before touching anything. A small accelerator pump shot would/should not disguise a heavily flooded carb. plenum.
Nice discussion...
