No gas when trying to start.

[Jim13]

I went to start the 74 Duster the other day and nothing doing. I wasn't getting any gas when i was turning it over. It is a 318 car with a 625 Carter on it.

I primed the front fuel bowls on the carb and it started right up and stays running just fine. I shut it down and started it a few times and it was OK.

If it sets more than half a day or so I have to reprime it to get it going and then it runs and starts fine again.

What do you think?

[ehostler]

That's normal for todays fuels.

[Jim13]

That's normal for todays fuels

Everybody using a carb has to prime it everyday?
That can't be normal.

I suspect it is the accellerator pump. I just wanted a second opinion.

This car is a daily so I am going to put an extra TQ on it until I can get a rebuild kit and a new acc pump for the 625carter.

[ehostler]

If the bowls are dry, how is the accelerator pump at fault?

Todays fuels evaporate quicker. They were designed to be in a pressurized fuel line.

Depending on where you are (fuel formulations are different), the bowls will dry out anywhere from a day to a week. Most people resolve the problem with an electric fuel pump.

[ttraut@unlockit]

Ed,

Your response seems a bit quick and (respectfully) not the useful "Ed Insight" that I've come to rely on.

I've never had to prime my carbs (thermoquad on the 383 or Holley 850 on my 440) even after sitting a month.

Maybe we're not reading Jim13's problem the same way. I'm reading Jim's problem as that he has to do more than crank the engine to fill the bowls. Somehow the fuel seems to have leaked out through the fuel pump and the pump isn't able to suck the gas. Therefore he has to put gas into the line above the pump to prime the pump.

Therefore, I'm thinking that there's something wrong with the diaphram on the fuel pump or there's a loose connection somewhere in the fuel line that would allow the gas to drain out of the line.

There's where my know-how ends. Ed, could/should the fuel line empty completely? If not, what might cause that problem?

Terry

[Chargerdude]

I agree with e, it seems the gas just dries quicker, and whats worse is mechanical pumps seem to be failing more often nowadays. I just bought a Holley electric pump to remedy the same problem. Gas just ain't what it used to be, it was better when it was cheaper!

[John Kunkel]

I have to prime any of my carbureted cars that sit more than a couple of weeks. I've added an electric fuel pump to most for that very reason.

It's the gas.

[ehostler]

A fuel pump cannot siphon fuel out of the bowls. The fuel enters the bowl through a valve at the top of the bowl. There are only a couple of way for the fuel to exit the bowls. The first is through the metering jets and into the carb. Then you have evaporation through the vent tube(s). Then depending on the design of the carb, leaky bowl gaskets. Last but not least, a cracked throttle body. A cracked throttle body would give indications of a flooded engine, when trying to restart after about 15 minutes of sitting.

Of course, it is possible that he is mis-stating what he is doing to get it to start. He states that he is priming the fuel bowls. That tells me that the bowls are dry and the he is filling them up through the vent. That would rule out his accelerator pump theory.

Now then, if he is just pouring an ounce or two of gas into the throttle plates, that could mean that the bowls are full and the accelerator pump is the cause.

Again, the fuel pump can't be the cause, as it is physically impossible for it to siphon fuel out of the bowls.

Also, as I stated, local fuel formulations will determine fuel evaporation rates. Different rules in different states will determine the evaporation rates. Just like winter fuels evaporate much quicker than summer fuels.

[Jim13]

I was pouring an ounce or two down the throttle plates.

It was not the fuel pump. I took the line off that had a neighbor crank it.

About 7:00 this morning I stuck an extra TQ on it and it started right up. I just went out a minute ago after it sat in the sun all day and it fired up withought hesitation.

This is a daily driver so I had to get it fixed now. I will rebuild that carb at a later date.

Apreciate the help.

[ehostler]

Now there is the difference. Your originally stated that you had to prime the front bowl to get it to start. Now you confirm that you are actually poring the fuel down the throttle plates. That means you were not priming the bowl.

That being said, I am inclined to believe that the problem is with the accelerator pump.

[Jim13]

[George G. Leverette]

Ed is correct about the fuel formulations, open the hood on a hot day after the car has reached operating temperature and you can see the fuel vapors. Add an aluminum carb and intake and the problem gets worse, now add a set of aluminum heads with headers and the car cannot even be started until it sits and cools down. Maybe that plastic bowl on the T. Q. works?

[kallyi]

This is from another Mopar site:

"I've had the problem with a 72 New Yorker, 440, 4160 Holley; a 66 Barracuda,
318, aftermarket intake and Edelbrock "AFB;" and on my wife's 67 Dart GT
with the smaller AFB.

In the real AFB there are plugs in the bottom of the bowls (I looked at them
during a rebuild), and they are said to leak (didn't know that when I
rebuilt it). I believe that to be the problem with mine, but have not taken
time to try to repair it. I did rebuild the carb, and it works wonderfully,
but loses fuel after a day or so.

I think both the other cars lost fuel due to heat "cooking it off" after
shutdown. The new Edelbrock "AFB" on the Barracuda did not appear to leak
fuel underneath. Maybe Edelbrock eliminated those plugs. In both cases, a
thick fiber spacer eliminated or decreased the problem. On the New Yorker,
the PO had used an aluminum spacer. The heat transfer with aluminum is
high, and I didn't notice a difference with or without that spacer.

The trouble and solution are much more clear-cut on the Dart. I'm not as
sure about the Holley. I think it was heat related."

I've also had the problem with Carter AVS, and AFB carbs, and it was the leaking plugs. They can be epoxied to seal them, but I usually just put an electric fuel pump on the car.

[moparman92]

Originally Posted by ehostler

If the bowls are dry, how is the accelerator pump at fault?

Todays fuels evaporate quicker. They were designed to be in a pressurized fuel line.

Depending on where you are (fuel formulations are different), the bowls will dry out anywhere from a day to a week. Most people resolve the problem with an electric fuel pump.

thanks I have been wondering about that because I also have a 1978 Olds 260 with cam headers intake and Eldelbrock carb and it it sits for about 2-3 days it will either drain back to the tank or evaporate mine pumps its self back up so no problems I just have been curious to why it does that and you reply seems to be the problem

[dgc333]

I had an issue that was very similar where the car would start real hard after sitting for a day or two or more. Once running it was fine, it would restart instantly within 0-30 minutes and after 30 minutes to about 2 hours it would crank for a few seconds before restarting. All the symptoms of the gas everyone was talking about. I had even popped for an MSD 6A box to try and improve it.

BUT, one day it would not start even with a blast of ether after filling up with gas, the coil had failed.

After replacing the coil the car can sit for weeks and it will start instantly, even after pulling the carb to change jets and putting it back on empty the mechanical fuel pump will pump enough gas into the bowls to allow it to start after 3 to 5 seconds of cranking. Still takes more cranking after heat soaking but it will start again within 2 or 3 seconds.

Guess what I am getting to is todays gas certainly is contributing but a weak ignition combined with a low fuel level in the bowls may be enough to keep it from starting and adding a little gas is all it needs. So, don't discount the ignition system as a contributing factor.

[mastogary]

I have two Holley DP on my runner and it was sitting for a while started up no problem....possible problem is cracked fuel line, bad pump, filter or needs carb rebuild..Thats my two cents

[70Ted]

i have 5 mopars with carbs, i have never had to prime any of them even after winter storage.

[don340-4]

Can someone tell me if an electric pump at the tank will push fuel through a mechanical pump so I can turn on the ignition & let the float bowls fill up before I try to start the engine? I have a 69 Road Runner 440 w/the original Carter AVS, the carb works beautiful but when it sits for a week or more the bowls go dry. Californias poor excuse for gasoline. Thanks

[440roadrunner]

I think this fuel evaporation "problem" is being vastly overstated. I can see a carb going dry after more than a week, maybe two. I've certainly not experienced this problem, even in hot summer weather.

I CAN see in certain cases that a defective (leaking) pump check valve,--and some actually do have bleed holes--might pull some gas back after parking, depending on the pressure/ vacuum situtation in the tank. I can also see that a very hot engine might boil some off and eject through the vent system, thus reducing the fuel in the bowl when things do cool down.

(I can tell you this--my original six pack RR was the first car I ever saw that had vapor return in the fuel line. When I put an electric pump on the car, and then experimented by leaving it off, I found out very quickly, then in S California, why this had been put on the car!!! My '69 383 RR had no vapor return)

Don340, electric pumps should work just fine through the stock pump. This is because the pump cam is not what builds pressure, but rather pressure is built up and regulated in the stock pump by the return spring. This means that as you drive, and the needles close, if the line has pressure, the pump arm will "float" on the cam. The same thing happens if you use an electric pump--the pressure of the electric simply floats the mechanical arm off the cam.

Just make sure you don't get some wierd high pressure pump

[RacerHog]

Originally Posted by Jim13

I went to start the 74 Duster the other day and nothing doing. I wasn't getting any gas when i was turning it over. It is a 318 car with a 625 Carter on it.

I primed the front fuel bowls on the carb and it started right up and stays running just fine. I shut it down and started it a few times and it was OK.

If it sets more than half a day or so I have to reprime it to get it going and then it runs and starts fine again.

What do you think?

Replace all the hoses and clamp and put a fuel pump and a new filter in it.....If the problem is still there....O.H. the carb...Problem fixed.....No brainer...

[don340-4]

440 Road Runner Thank you for the explanation on how the pumps work, I will get a Carter street pump i think has 4 to 6 psi, RacerHog i will go tomorrow & get the filter, fuel lines & pump. Thanks again for the help.