Gas

[rich morrill]

When my car sits for a few days, the gas in the carburetor seems to drain back I have replaced the carb and the fuel pump. Anybody have any other suggestions.

[jwoodsmall]

Rich:
I havent got an answer but I do have the same problem, and have also replaced the fuel pump and a new carb. I hope someone has an answer!
Jim

[earlybirdlover]

It seems that this problem is normal. Alot of people install an electric fuel pump wired to a switch on the dash and use it only for a few moments to fill the carb prior to starting. Hope this helps. Jim

[t-bird-art]

Fuel draining out of the bowls is caused by many things.Idle screw is set too high or a dirty/cracked/abused carb or a poor/incorrect rebuild. The gas leaks down the carb into the engine. I does not leak back down thru the fuel pump. If possible return to rebuilder to do it right ( until the bowls stop leaking on a 1 week bench test ).

[earlybirdlover]

Probably the #1 cause of your problem is fuel evaporation. If your problem happens after only a day or so, I would say you have a leak like the above post states. If it happens after several days, the problem is evaporation and there is basically nothing you can do about it except the electric fuel pump trick I stated above. I've had many non-fuel injected cars over the past 35+ years that have had the same problem.Good luck, Jim

[t-bird-art]

There is evaporation of gas from the bowls or what appears to be evaporation. I bench test loss of gas from the bowls for a week. If , after a week, I don't have at least a 1/4 bowl of gas ( enough for the accelerator pump to pick up gas and start the engine) I re-inspect everything: venturi , gaskets, adjustments etc.

[rich morrill]

I contacted Jim Weatherly who rebuilt my carburetor. Jim Informed that if I wanted to he would recheck my Carb. He also said that a lot of people have the same problem wth older style carburetors, they are not sealed and tend to allow the gas to evaporate quicker. The newer style gases also evaporate faster than when the gas had additives. It seems to make sense to me.

[t-bird-art]

I agree . The 40 year old carbs have been recycled and messed with many times. ( Overtightened screws/ bolts - burned/warped with backfire - orfices cleaned with piece of wire - incorrect/broken/plugged venturi - incorrect bench reassembly/adjustments etc ). It' no easy job to get these old carbs to hold gas. The best to hope for is one that will hold enough gas for the acellerator pump to pick up gas to spritz into the intake manifold for 7 days.

[earlybirdlover]

Originally Posted by rich morrill

He also said that a lot of people have the same problem wth older style carburetors, they are not sealed and tend to allow the gas to evaporate quicker.

That's the problem I and all my buddies been dealing with for years.

[Brian]

I had Holley restore and rebuild my carb - but alas, it isn't on the manifold yet. I'll let you know down the road how it handles this problem.

[t-bird-art]

Brian: Very good. You have a good test carb. Before mounting on car, fill bowls and watch gas level daily. Use (4) bolts to get the carb up off the table/bench so nothing (linkage) touches the bench. Back off the idle screw so idle passages are completely closed. Don't know where you are. If it's freezing test in a cool dry place for a fair test. Let us know.

[earlybirdlover]

[quote=t-bird-art If it's freezing test in a cool dry place for a fair test. Let us know.[/QUOTE]

That will work if you're checking for leaks and eliminating that as the problem. This isn't a good test to monitor evaporation rate though. Remember, after you drive your car and shut it off, the carb & fuel will be heated to 200 degrees or more and then slowly cool off over a period of hours. Unfortunately, this rapidly increases the evaporation rate of the fuel. Good luck, Jim

[t-bird-art]

Good point Jim. I have seen gas boiling in the bowl after engine was shut down ! Why ? The cheap/ useless gasket supplied with the carb rebuild kits that goes between the carb and intake manifold. Got to put things back the way Ford put them together. Over the years Ford used many gaskets / heat insulators / water cooled spacers to keep engine block heat away from the carb.

[t-bird-art]

-One thing leads to another ! Years of rust/calcium/lime have settled to the bottom of the engine blocks. The trash stores heat which is released when car is shut down. (Block heat + trash heat sometimes is enough to boil the antifreeze and it comes gushing out the radiator cap ) . A clean block is a happy block.