Carburetor going dry.

[JSmithTN]

I have a 340 6 barrel, that I am using ethanol free fuel.

I'm having an issue, if the car sits for approx. 2 weeks the carbs going dry and I am having to prime it multiple time to get the bowls to refill.

I would like to see if anyone has experienced the same problem and what it took to resolve the issue.

I know that I can put an electric fuel pump on it, but that is just a solution and is not fixing the problem.

Thanks in advance for any help.

Jeff

[MoparLeo]

So are we to assume that this is a new carb setup and has always had this problem or is it something that just started recently ?

[tparker]

I have an old '67 D100 pick up and if it sits more than a few days it will have take a bit of turning over before it will start. I could be wrong, but my understanding is that modern fuel evaporates fairly quickly. But that seems like a fair amount of fuel to evaporate out. If it is true, I doubt there is much we can do about it. My Motorcycle is the same.

[Rich G.]

I believe it's the crappy gas that's made today. I have 4 carbureted vehicles and I have to crank them all 2-4 times to get them to start if they sit more then a week. Fires up instantly the rest of the times.

[70vert]

I have the same issue, though not the same "specs". Mine is a 70, 440, and I do not use ethanol free. If it sits for a few weeks or more it is dry and I have to crank it several times and pump the gas pedal before it starts. I know that is not great on the engine internals ):  For me there is also a slight raw gas smell in the garage after driving the car, but I can find no signs of leaking


In fact I just replaced the mechanical fuel pump, which did not fix the issue. My plan was to next change the carb. I'll be interested in feedback you receive, thanks.

[Filthy Filbert]

This is normal.  Fuel is volatile.  It evaporates quickly. 

It is not your fuel pump.  don't waste your money.   If it bothers you to crank the motor for 10 seconds before you "set the choke"  to fill the fuel bowls back up, then the only thing you can do is add an electric fuel pump.     

[erat340]

My experience also. Finally found a solution blocking off carb heat in the intake crossover.... and ,yes, it is the crap fuel. I now have an air gap, no problems.

[torredcuda]

If the bowls are actually empty it is either evaporating or leaking out of the carb. Dirt, worn needle/seat can cause a leak.

[Racer57]

I have a 2 yr old Holly carb with electric choke.  If my 383 sits for couple weeks or more its a guessing game how much to pump without flooding it.

[chargerdon]

Both my 66 Charger with 383 and Edlebrock 600 CFM carb, and my 74 Challenger with 360 and same edlebrock carb also edlebrock RPM Air Gap intake have the same issue.   Both have mechanical fuel pumps.   The gas evaporates out after about 5 days in either of them starting takes a while.    I believe all of us with cars that sit have this problem...yes, and electric fuel pump can help this but who really wants those noisy expensive fuel pumps ? 

My solution is simple.    When car sits for more than 5 days, i first will crank it for about 3-4 seconds to get some gas back in the bowls....   Then i take off the air cleaner and pour in about an 1/2 ounce of gas straight down the carb...   Both then start immediately when cranked and run fine.   Put the air cleaner back on and ready to go.   Yes its a pain, but, i don't like to have to crank too long and also possibly damage the accelerator pump.   

[rikkitik]

 Mine does the same. As others have mentioned, it's not uncommon, (my carbs, 6 pack, are in perfect condition), TF 240 heads, so no heat riser provision. I have gotten into the habit of pulling the air cleaner and filling the center carb through the vent. Once I get off my dead ass, I'm going to install an electric pump to prime with.
One thing that makes me a bit curious. I wonder how many flat tappet cams have been hurt/scuffed by extended cranking, after sitting for a while? Potentially the cause for engines that "ran fine" for months, then suddenly the cam goes flat. Definitely a possibility.

[70vert]

My solution is simple.    When car sits for more than 5 days, i first will crank it for about 3-4 seconds to get some gas back in the bowls....   Then i take off the air cleaner and pour in about an 1/2 ounce of gas straight down the carb...   Both then start immediately when cranked and run fine.   Put the air cleaner back on and ready to go.   Yes its a pain, but, i don't like to have to crank too long and also possibly damage the accelerator pump.

I do similar except I use Starting Fluid, spray into the air cleaner snorkel. Not sure if that is better or worse on the engine internals than pouring gas, but easier and starts right up.

[Racer57]

I would love to squirt gas into the carb. But I have a shaker and its the only time I wish I didn't have it. 

[MoparLeo]

It is not a fuel pump problem.
The carb bowls have fuel when you shut it off. The fuel pump only supplies fuel to the carb.
As Said above, either dirt in the fuel bowl allowing fuel to leak out through the needle/seat when shut off and/or fuel evaporation.
Since the previous owner said he had the same problem and you say it is intermittent I would lean towards dirt in the fuel bowl.
I would change/install a fuel filter between the fuel pump and the carbs.
Remove the center carbs fuel bowl and metering block. Check for dirt/debris. If it is dirty, figure the other 2 carbs are dirty as well.
Cheap way, remove float /needle assembly and blow compressed air through the metering block and inlet fuel opening, replace bowl gaskets OR
Bite the bullet and have the carbs rebuilt by a person/company familiar with the Six Pack carbs and have ethanol resistant parts used, Also check the gas tank for dirt/debris. Remove fuel tank sender and check the sock for contamination. If so, you will next need to remove the tank for cleaning/replacement.  Be carefull as gas is flammable...

[torredcuda]

It is not a fuel pump problem.
The carb bowls have fuel when you shut it off. The fuel pump only supplies fuel to the carb.
As Said above, either dirt in the fuel bowl allowing fuel to leak out through the needle/seat when shut off and/or fuel evaporation.
Since the previous owner said he had the same problem and you say it is intermittent I would lean towards dirt in the fuel bowl.
I would change/install a fuel filter between the fuel pump and the carbs.
Remove the center carbs fuel bowl and metering block. Check for dirt/debris. If it is dirty, figure the other 2 carbs are dirty as well.
Cheap way, remove float /needle assembly and blow compressed air through the metering block and inlet fuel opening, replace bowl gaskets OR
Bite the bullet and have the carbs rebuilt by a person/company familiar with the Six Pack carbs and have ethanol resistant parts used, Also check the gas tank for dirt/debris. Remove fuel tank sender and check the sock for contamination. If so, you will next need to remove the tank for cleaning/replacement.  Be carefull as gas is flammable...

Fuel pump and drain back should not affect initial fire as that is done from fuel already in the bowls, if you have no fuel in the bowls then it is leaking or evaporating. My car has been sitting for around 3 1/2 weeks without being started, the bowls are still full and fuel squirts when you hit the throttle. I understand temperature affects how fast fuel evaporates but I think that issue is blamed a lot more than it actually happens, my bet is carb needs a rebuild. I had a similar issue with mine - had to pump a lot when cold and floor it when how, once I replaced the needles and seats the issues went away.