The fuel magically disappears from my carb!

[moparedtn]

I have an Edelbrock 750cfm AFB type carb on the 440 in my GTX and I've gone through it, even though it was supposedly "rebuilt" (it's even stamped as such).
Everything, and I mean everything, on this car has been replaced and is new and it runs great once it gets going.
It simply won't keep fuel in the bowls after it has sat for a day or more.

It goes pretty much bone dry after it has sat for a while, leading to that annoying long cranking session the next time I go to fire it up where the fuel pump has to draw up gas and get it to the carb all over again.
I figure that's not good for the starter or the fuel pump over time.

Is this just the ethanol in the gas causing this?

 

[383MovingViolation]

Yes, I have the same thing going on with mine. I hope someone has an answer. Thanks

 

[GetX'd]

I never could figure out the why's of my fuel flow problem so I finally put a Mr. Gasket electric fuel pump on the car - the problem was magically resolved and has yet to reappear.

 

[PP1RT]

And you have the phenolic spacer under the carb too?

 

[coloradodave]

Carburetors are vented to the atmosphere and the new gas has a very low evaporation point. The answer is fuel injection which is a sealed system, like modern cars. As was said, an alternative is to install an electric pump at the rear to prime the carburetors before cranking.

 

[1962polara]

Member here ,Frank(62dartconvertible), had the same issue.He added a fuel pump but still didn't solve the issue.
He ended up finding he needed a vapour return line AND a wooden carb spacer.



http://www.forbbodiesonly.com/moparforum/threads/carter-electric-fuel-pump-failure.119723/

 

[Billccm]

I have the same carb and similar issue if my car sits for a week, or more. I assume evaporation. My friends chevelle and el Camino act the same, too.

 

[Mopars & Missiles]

This is very common to these cars. Doesn't matter if its an original Carter or aftermarket Edelbrock. It is the nature of mopars with carburetors of the '60's & '70's. I would venture a guess that other makes (Fords/Chevys) of that era with carburetors also had this issue, but since I've never had anything but a Dodge, I don't know for sure. Mine has been that way for the last 44+ years, so its not just the type of gas.

GetX'd and Coloradodave are both right, a closed and pressurized fuel system eliminates the issue, or an electric pump to pre-prime prior to starting.

 

[steve817]

I have the same carb on my 440 and if I leave it sitting for a week, I just pour fuel down the vent holes to fill the bowls a bit and it fires right up.

 

[idrivemopar]

I have the same carb on my 440 and if I leave it sitting for a week, I just pour fuel down the vent holes to fill the bowls a bit and it fires right up.

I do the same thing, I just have a little squeeze bottle that I use to fill the carb up and good to go! I don't remember this being a problem back in the 80's, but it was also my daily driver back then!

 

[ckessel]

Welcome to the wonderful world of gas with alcohol added in! Lower boiling points on the fuel causes it to boil out/vaporize out. Lots of info has been going back and forth here so there is a plethora of ideas to check out and decide upon. My car is going to be EFI so this should be a dead issue for me.

 

[moparedtn]

And you have the phenolic spacer under the carb too?

Yessir.

 

[451Mopar]

I think it is just what they use for gasoline these days?
Race fuel seems to be better. A friend in the car club filled two glass jars, one with pump gas and the other with race gas, and checked to see how long it took for the gas to evaporate. The pump stuff evaporated much sooner, and left a yellowish residue in the jar. The race gas took much longer to evaporate (I forgot the duration, this was done maybe 5-years ago), and it did not leave any residue except maybe a light color from the fuel dye.

 

[Dennis H]

Ethanol. Cold dead hands will I give up my 850 Mighty Demon. 3 stomps to the floor brings mine to life. 1/2 spacer, wrapped lines, etc. A brief stint with a 150 GPH Edelbrock Street electric pump did not seem to mitigate it for me. Went back to mechanical. Mopar HP.

 

[khryslerkid]

Hey Ed, just curious, what's your operating temperature now days. Thought you had her cooled down quite a bit.

 

[oldbee]

Ed move to Ohio- doesn't evaporate for 2-3 days, lol.

 

[eldubb440]

I ran a pair of eddys on an amc for years........if enough time goes by, the accelerator pump plunger shrinks; and even after the bowls are full, it wont squirt until it swells back up ...... other than that they were trouble free

 

[Kern Dog]

The 850 Demon in my 440/493 Charger can sit for weeks and still start up fine. THIS is even with the California blend of pump gas. NO spacer, NO electric pump.
The Holley 600 in my 75 Power Wagon can also sit for weeks and still start fine. Neither has a functioning choke either.
I had a 73 Dart Sport 340 with a ThermoQuad. It was hard to start when cold or after sitting a few days. I blamed the problem on the accelerator pump....BUT once I attached a proper choke to it, it started up easy even after a month of sitting. No ****, I was shocked! For years I have bitched about ThermoQuads being a POS carb but maybe I was to blame the whole time!

 

[threewood]

Live with it or get a loud *** electric fuel pump. I have Edelbrocks on two cars, both run great. One has an electric pump and one has a mechanicsl. The electric pump starts on the first turn. The other, well, it does not.

 

[moparedtn]

Hey Ed, just curious, what's your operating temperature now days. Thought you had her cooled down quite a bit.

Yessir, running quite a bit cooler.
Took her out for an extended drive just yesterday, in fact. Ambient was low 80's.
The GTX ran consistently about 180 for the whole trip, mixed backroads and some 60-65mph towards the end.
She does heat soak some when I make the climb up our private gravel drive (elevation gain of a couple hundred feet up here to the ridge) and then park in the garage; still spits a little out the overflow once I shut her down.