here's my combo. 70 340 Cuda, 727, 3000 stall, 3.73 gears, mopar 484 cam, MSD Ignition, 12*initial, 30* total timing all in by 2500. recent tune up including fuel filter, 5/16 fuel lines new

Car has developed a hesitation under hard accelaration around 4200 RPM, Falls flat, no backfiring or anything just cuts out, let off the gas to allow it to "catch up" and it takes off from there to my self imposed 5500 red line. Symptoms get worse as motor gets more and more warmed up.

I found the accelarator pump to be a little weak so I changed it and replaced fuel pump with new carter mechanical pump for good measure. while carb apart for acc. pump change, I cleaned and blew out all the passages and checked the float level, 7/16 and 1" per manual blew through fuel inlet while operating floats to confirm needle and seats working, everything checks ok. once assembled, car ran like a bat outta he..

Cut to one week later, hesitation comes back. I look at acc pump shot and it's weak again like ther's too little fuel in the bowls. getting broken stream. I've been through 2 differnt tanks of gas, checked and rechecked ignition. I'm tempted to raise floats to allow more fuel in bowls but I know the float range is within spec. I borrowed a friends 750 demon carb and while it was jetted a little rich for my combo, it cured my ills so I know it's in my carb.

I guess my question is why is my acc pump shot so weak and how high can I go with the fuel level in the bowls before flodding? I think the acc pump is good, (1 week installed new edelbrock), just starving so where is the fuel going or not going.

Thanks

You'd have to have very little gas in order for the accelerator pump to go dry. I would leave the floats set by the book.

If it's low on fuel could it not be the fuel pump or maybe a slight air leak in the fuel lines? Might check the rubber hose connections too. They dry up with age and can leak air.

Thanks for the reply Neil, I just checked the rubber lines and they look good, fuel pump is new, changed during first troubleshoot and confirmed problem in carb by running friends demon. I didn't check pick up sock in tank but car runs good with friends demon on it.

I see 2 seperate issues.If you poured a little gas into the bowl vent & if that restored the ap stream that would tell you that the AP is good & that the fuel is evaporating(very common w todays gas) or leaking. Is this what you are seeing 1st thing before you take it out? 2nd I would soak the carb in the soup & put a new kit in it AFTER I hooked a gas can to the pump inlet in the eng compartment & go for a spin to check the fuel system from the pump on back including the sock. I know the other carb did OK(for the one occaision) but those are my

Thanks Robert. I am checking the pump shot after cruising so I know it's not evaporating. Our gas down here stinks, 10% ethanol, I'm on my second tank from differnt stations. My crappy little fuel pressure guage reads 3.5 to 5 psi at idle and reving it up in park. carb sits on 1/2 inch 4 hole phenolic spacer. I've run car with and without gas cap. I think I'll wait until fuel tank gets lower and just visually check tank pickup sock.

The symptoms sound like textbook fuel starvation from the fuel delivery system. If you hooked up a gas can in the eng compartment to the pump inlet & went for a spin I believe you'd have an answer in <30 minutes.

I'm off to get some fuel line, I'll rig something up to test. probably won't be until tomorrow that I'll have results. Thanks for your assistance

Garrett

I had this problem with a freshly restored AVS carb.
I took it back to the guy who did it, and he determined that there was a run of defective accelerator pumps out there, and that I had one!
We went through three or four before we found one that would deliver a consistent shot of fuel.
It happens to even an expert on Carter carbs.

Thanks rm, I haven't ruled that out as well. With all the techron, ethanol, etc in the gas here, it's gotta be rough on rubber parts. today I puled sending unit, sock not too bad. ordered replacement sock, acc pump and carb calibration kit. I will get to the bottom of this as soon as parts arrive.

Which carb do you actually have,AFB or AVS ? Also,have you checked the ball check valve in the bowl to accelerator pump well to make sure it seals.This littlle guy here.

It's a 625 AFB, electric choke. There is a check ball and weight in the passage leading to the pump discharge nozzles and it's clear of debris. The one you have pictured looks like one of my jets , I don't recall seeing that type in mine. I am going in again once parts arrive in mai

Thanks

I've found that the Carter carbs have problems with the E10 gas that we have around here. They grow a white slime inside the fuel bowls that can plug up passages. I haven't had the same issue with Holley carbs so I think it is a chemical reaction.

When I had a Carter carb (actually mfg by Weber in my case) on my truck I had to open it up a couple of times each winter and clean it out. It was only the winter gas mix that caused problems, not the summer gas.

I didn't notice any white film like that, Andy. Just about a couple years worth of varnish since the last time apart. I keep the gas fresh and add alittle marvel oil to the gas every once in awhile. Our winter gas seems ok, it's the summer stuff you have to look out for here in S Fla.

this summer in central FL,my eddy went to flooding every time I drove it

swithed to a Q-jet it went about a month till the same thing

put a kit in they eddy and its fine now

I found a lot of varnish and grains of rust colerd crap all in it

same thing in the Q-jet

they switch gas and I have had no more probs since

I would soak it,give it a good blast of air to clean passages just for good measure anyways IMO

with the price of gas I going back to the Q-jet, its much better on the MPGs,I was at 19 mpgs in a truck and down to 12-13 with the eddy

just a change in carbs is a big diif

That is excellent advice 62maxwgn, thanks. I will make sure I check that as I know I did not before. I think I thought that was just a passage and didn't know there was a ball check in there. That looks like a great place for crap to hide

I'm back looking at the carb today and I don't have a ball check valve in that location as shown in the pic above. how exactly does the accelerator pump well get filled? Is the fuel level in the bowl supposed to be high enough to spill over into the well via the long vertical slot between the fuel bowl and the well or is there another intake passage that I'm not aware of?

Thanks

btt