Why isn’t fuel going to the carb?

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Can someone send me some pictures of what their filter, supply line, and return line setup looks like?
 
The OEM return was only fuel vapors from the bowl vent on the OEM carb. There was a charcoal canister with flow check valve.
Maybe some do use this metal pipe for a liquid fuel return. My questions , Can all the fuel go that route? Will fuel pressure delivered from the pump push any fuel through the tiny orifice into the bowl? How long might it take to fill the bowl if there is no restriction in that return path?
You might answer some of these questions with a clamp on that return hose.
 
Some stuff:

Where did you get the idea for that filter? I bet it was not like that earlier

As Redfish eluded to THESE CARS DO NOT HAVE A RETURN as built. There are originally TWO tubes from front to rear of the car

One is the fuel supply to the inlet of the pump and is normally 5/16"

The other (as far as I know) is a 1/4" tube and IS THE VENT FOR THE TANK. It originally hooked into the "carbon canister" system, otherwise known as "evaporative emissions control."

DO YOU HAVE a factory service manual? If not, download one for free from MyMopar. No I don't work there. Some of them there came from the guys on here
 
RedFish said:
The OEM return was only fuel vapors from the bowl vent on the OEM carb. There was a charcoal canister with flow check valve.
Maybe some do use this metal pipe for a liquid fuel return. My questions , Can all the fuel go that route? Will fuel pressure delivered from the pump push any fuel through the tiny orifice into the bowl? How long might it take to fill the bowl if there is no restriction in that return path?
You might answer some of these questions with a clamp on that return hose.
Click to expand...

I agree. I removed the purge canister system from my Dakota when switching between carbs and EFI sytems (multiple times) and have used the canister hard line for either a return or vent depending on my requirements. I believe with that T hooked up you have NO vacuum being pulled by the mechanical pump and even if you can get it to prime you cannot maintain 5# - 7# fuel pressure at the carb. Block the T, prime the fuel bowl, ensure enough gas in tank for new pickup and you should be good to go.
 
Yup, your pulling a vacuum that way, deadlocking the whole fuel system
Pop the gas cap of and try it again
(That will allow the fuel neck to act as a vent, which you do not have now)
 
Marcohotrod said:
Wrong filter. Carburetors do not use a return fuel line
Click to expand...

Actually YOU CAN and carburetors (some) DID HAVE a return line. Hemi cars and my 440-6 had them from the factory.

BUT THIS FILTER is situated wrongly.........the return must be "up" to trap air at the top

And whatever it is hooked up to is wrong. A SEPARATE line must be added to use these, or else the vent system re-worked.
 
Thanks for all your replies! I actually got it running yesterday for the first time. The fuel started going to the carb. I just needed to pour gas in the carb a while until the pump began working. I’m guessing the fuel filter is okay then, since it was running for at least five minutes.
 
Dakota Smith said:
Thanks for all your replies! I actually got it running yesterday for the first time. The fuel started going to the carb. I just needed to pour gas in the carb a while until the pump began working. I’m guessing the fuel filter is okay then, since it was running for at least five minutes.
Click to expand...
Sounds ok
But if you go out for a drive and it dies on you, keep my advise in mind and pop the gas cap off
 
Marcohotrod said:
Wrong filter. Carburetors do not use a return fuel line
Click to expand...
Agreed, the only time I have seen return lines is on fuel Injected engines and Diesels which are fuel injected. Unless that is some kind of California emissions, I have never seen a filter like that on a carbureted Mopar. It reminds me of those inline power steering or AC Buffer filters
 
67Dart273 said:
Some stuff:

Where did you get the idea for that filter? I bet it was not like that earlier

As Redfish eluded to THESE CARS DO NOT HAVE A RETURN as built. There are originally TWO tubes from front to rear of the car

One is the fuel supply to the inlet of the pump and is normally 5/16"

The other (as far as I know) is a 1/4" tube and IS THE VENT FOR THE TANK. It originally hooked into the "carbon canister" system, otherwise known as "evaporative emissions control."

DO YOU HAVE a factory service manual? If not, download one for free from MyMopar. No I don't work there. Some of them there came from the guys on here
Click to expand...
The car had a return line already when I started working on it, so that’s why I got that filter.
 
Dakota Smith said:
The car had a return line already when I started working on it, so that’s why I got that filter.
Click to expand...
See, that's where you are wrong
(At least, judging by the pictures)
What you mistook for a return line is actually a tank vent
That line should have gone into a charcoal canister which would allow air to enter the tank, but reroute air coming from the tank into the intake (while there is engine vacuum present)

Now, with that canister missing it is pretty easy to look at it and think it is a return line, but by hooking it up like you did, there is no way for air to enter the tank, as the pump pulls out gas...it seems to me you are forcing your tank into a vacuum situation
 
open this quote up, and look at the pictures
thats the way it should be
(then read the article on the very bottom to explain how the whole thing works)

diymirage said:
that will work

the way i have mine set up is as follows (aftermarket add on to a 71 duster)

i have the tank vent running into the canister
the purge line T-ed into the PCV line
and a purge valve connected to the vacuum advance line
(so the can will not purge into the vacuum advance system, but the purge valve will allow the canister to empty into the PCV system when there is enough vacuum)



tank vent line

View attachment 1714992866

the canister

(bottom line is the tank vent, top is the purge line)

View attachment 1714992867

and where it is Teed into the PCV line
(you can see the purge valve on the far right, Teed into the vacuum advance)

View attachment 1714992868

the whole system was put together based on the advice @slantsixdan gave me, and all parts were aproved by him

(here is an article explaining the whole working of it Fixing 1970s Evaporation Control Systems )


now, there is still some fuel smell from the carb, but way, WAY less then before
Click to expand...
 
diymirage said:
See, that's where you are wrong
(At least, judging by the pictures)
What you mistook for a return line is actually a tank vent
That line should have gone into a charcoal canister which would allow air to enter the tank, but reroute air coming from the tank into the intake (while there is engine vacuum present)

Now, with that canister missing it is pretty easy to look at it and think it is a return line, but by hooking it up like you did, there is no way for air to enter the tank, as the pump pulls out gas...it seems to me you are forcing your tank into a vacuum situation
Click to expand...
That makes a ton of sense because there was a mount for some kind of canister right beside what I thought was a return line. I didn’t know what it was for, so I took it off. Thanks!
 
you got @slantsixdan to thank for that, he is the one who pointed me in the right direction when i put my charcoal canister together

i think what certain people dont realize is that you are working on a car that is almost 20 years older then you are and the mistakes you made are pretty easy to make, if you werent around to see where that line went in the first place.
(its easy for them to see what the picture should look like, because they have seen the box, but your trying to put a puzzle together with a few pieces missing)

now the question becomes, how are you going to deal with it, now you know what it is?
 
Without the charcoal canister you will smell fuel. Especially if you park it in a garage.

Someone pulled the canister on my 77 jimmy,it stunk of gas all the time. I robbed a canister from something and plumbed it in. Smell gone.
 
Tooljunkie said:
Without the charcoal canister you will smell fuel. Especially if you park it in a garage.

Someone pulled the canister on my 77 jimmy,it stunk of gas all the time. I robbed a canister from something and plumbed it in. Smell gone.
Click to expand...
mine don`t, I have never smelled gas in my garage.-------from that . Course it didn`t come out w/ a canister on it to start with.
 
Dakota Smith said:
Can someone send me some pictures of what their filter, supply line, and return line setup looks like?
Click to expand...
This may sound stupid but take the line going to the pump off, put your finger on the pump suction fitting. Have someone crank the engine see if you have suction, if you don't pull the pump, check the pump arm and make sure you have an eccentric on the cam. If you do have suction try blowing compressed air in the tank and see if fuel comes out the fuel line at the pump.
 
Dartswinger70 said:
The "flow" arrow is pointing toward the Carb, then yes its hooked up correctly. I have never seen a filter with T hookup like that. What is the purpose of that?
Click to expand...
return line to prevent vapor lock by letting fuel always circulate rather than just sit there and get hot, orficed nipple
 
james m smith said:
return line to prevent vapor lock by letting fuel always circulate rather than just sit there and get hot, orficed nipple
Click to expand...
When did these come about, I grew up driving late 60's 70s cars never seen it. Now if it was on later 70's cars I may have never seen it. never owned late 70's Mopars. Anyway, did the OP figure this out? I thought he got it running
 
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