Hot Rods Edelbrock afb leaking fuel in intake

Off shore?????
Say it like it is
In foreign lands by foreign hands where our money goes

 

You know what? I might try the spacer. I have another car with a small block chevy and an edelbrock carb. Just like the one giving me fits. Sitting in the SAME garage, and that car always starts. The difference is THAT car has a phenolic spacer and the trouble car does not. Yup. Now I know what I'm doing tomarrow!

 

I would agree with this starting process as it’s what I do with my old chariot. This new fuel does “boil out” of the Edelbrock carbs especially if they are not run for a while so I run the starter until I see oil pressure, flick the kill switch to “run” floor the pedal once to set the choke and hit the key again. Usually starts this way. Hope this helps.


Sent from my iPhone using The H.A.M.B. mobile app

 

Genuine Carter AFB's have an evaporation problem (I have an electric pump on my OT shop truck with 2 AFB's because of this), however:

Just one of the many changes the F/M accountants made when they redesigned the AFB (read clone) after F/M bought Carter, is they changed the time-tested pressure casting technique to the vacuum casting technique used on the much smaller BBS and BBD carbs. The vacuum casting process produces castings which are less dense (read porosity issues).

Jon

 

Well, I put on a spacer and a heat shield that I had in a stash. Started it up. Ran it for 10 minutes. Shut it off and now I wait. We will see what happens.

 

Well. Been a week since I put on the spacer and heat shield. When out to start it, and nothin! Same shit. No fuel in the carb. Cranked the hell out of it. Still no accelerator squirt. Gave it a shot of carb clean and bam. Fired right up. So I'm thinking I'm going to put a fuel pressure gauge on it. I'm starting to think the carb is just going to evaporate the fuel no matter what. I'm going to make sure the fuel pump is doing it's job to fill it up. Starting to run out of ideas. I hate that, because I feel like there's gotta be a way to fix this.

 

Sorry but I'd chuck that sucker for a different leaker. Lippy

 

Throw that Eddy as far as you can...……………………………..

 

I like it when reality sets in....

 

I have found that if you put a one way check valve in the line just before the carb, you will cure this issue. Most of say the fuel leaks into the engine, a bit does, but the bulk siphons back into the fuel line thus emptying the bowl. Give it a try, i think you will be surprised.

 

How about a part number dickster?

 

Tell you what, send me a $10 bill and I will send you one. PayPal is [email protected].
Cheers,
Dick

 

Done deal! Check your PP account!
Will send you a used to be called a PM with addy to send to!

 

Aye, Aye Sir.

 

Sorry I ain’t buying the siphon out of fuel bowl. A check valve will probably keep the fuel right there ready to go quickly next start and that’s quite beneficial. Like putting your finger on the straw. Simple easy and good idea.

That shit fuel is going out of a hole. Either the damn thing actually does have a hole and it’s dripping out (all the time delivering unmetered fuel) or it’s evaporating out the vent hole like everyone else’s.

The siphon notion ends as soon as there’s an air break at the feed inlet which is at the top of the fuel bowl.

You’re car hits the fuel pump around 90 times a min cranking at 90 rpm on the starter. A prime of fuel starts the engine and that hits the fuel pump 900 times a min figuring it’s 900 rpm. Obviously re established pump prime and filling the fuel bowl 10 times faster without hammering the starter motor.

The pragmatic approach would look at where and when this happens first,,,, sitting in your garage. The easiest way to go around this is put a sealed squeeze bottle of fuel on the shelf and give the carb throat a shot of fuel when you want to go.
The problem could be gone around by overthinking, over reacting and over complicating by installing an electric fuel pump that you’re going to be dependent on 100% of the time. Saves you the trouble of opening the air cleaner

 

Another approach is to add an electric pump in line (the pulsing kind), powered by a push button, and only use it before you start the car.

 

Doesn’t that solenoid pump create a restriction in the line for the mechanical pump to overcome? And then that electric inline would have to push thru the mechanical pump to fill the bowl.
I’d have to test that one out but that could work and save opening up the air cleaner too.
I’ve got the stuff here, I should run a test on all that.

I’ve set up inline pumps on oil pressure safety switches and installed a momentary primer button for this very reason.
A key on pump on set up bugs me a little bit and manual fuel pump switches seem to bug most folks I get to meet.

 

I didn't know if it would work, but I tried it on the Hudson last year...worked fine. Athough it's problem was with heat, not evaporating. But I only had to turn on the electric pump when it was either real hot out, or if I wanted to make it all the way up a hill. Or to prime the carbs after sitting a while.

 

So a lot of you guys blame the evaporation on shit gas. And I agree,this new gas is junk. But the thing that gets me is I have another edelbrock carb on another small block chevy with another stockish fuel pump. And that cal ALWAYS starts. Even after ALL winter.in the SAME garage. I might swap carbs on the 2 cars and see if the problem follows the carb

 

that will be an interesting test.

 

I have a 350 with a stock pump and a holley carb. Left it ALL winter. Started right up with the same shit gas I put in it last year. . Did I mention I would put another carb on it? What about that cardboard test you did? Fuel must be leaking out of the bowl into the throats somehow seems to me. Lippy

 

All carburetors on V-8 engines (and to a much lesser degree, inline engines) are subject to evaporation, depending on the distance the carburetor is away from the heat.

Holley carbs tend to have less evaporation issues than any other, as the fuel bowls have an air-gap of insulation between the bowl and the heat source.

Spacers can help the issue, but rarely completely cure it. While probably not an issue with most that frequent these forums, spacers in thickness greater than 1 inch can effect the idle quality (but can also add a marginal amount of power at W.O.T.).

With genuine Carter AFB's, leakage (unless broken or porous, and Carter didn't have a porosity issue until the F/M redesign) cannot occur as there are NO gasket surfaces BELOW the fuel level in the bowl. It is also impossible for the genuine Carter AFB's to syphon fuel from the carburetor back to the tank (unless the vehicle is parked on its top ), as the fuel valves are ABOVE the fuel level in open air (no closed passages).

The fuel syphoning was a huge issue on some of the early Q-Jets, especially the performance versions with the "windowed" fuel valve seat.

Jon.

 

I have been working on a friends car with this issue.
The gas is evaporating.
I took the top off of the carb just after getting it started, to see if I could find any issues. I’ve never worked on one of these before, so I went in with an open mind. I disassembled it cold, as to eliminate the heat/evaporative factor.
The carb has two jets per side. Each side has them at different levels from the bottom of the fuel bowl. I figured one of the jet ports would be the culprit. I let it sit all day open. Every hour, I would take a look at it. It continued to drop the fuel level at each inspection.
Now, each side is self contained, so I didn’t expect them to drain at the same rate... but they did. Finally they got to the highest jet. They both continued to drop. Then to the second jet... still continued to drop, until one was totally empty, and the other was just damp.
Now, the fuel bowls are cast, with no other path for fuel drainage. This made me believe the evaporative issue was real. I didn’t stop there though. I filled the one side with regular pump fuel, and the other side with 50:1 “truefuel” from my weedeater. I ran the same test. The regular fuel side was empty in about 5 hours, the other side was right where I filled it to. I believe these carbs need a smaller or closed vent system to prevent this from happening.

 

I'll ask again, why was the cardboard wet if it's all an evaporation problem? Lippy

 

After reading this whole thread it seems that the final issue is that it’s hard to start after letting it sit for more than a day or two. I have the same problem. My ‘56 Chevy with an Edelbrock carb and my wife’s Corvair with factory carbs both do the same thing. They often sit for a month or more.
I was thinking that this is allowing the accelerator pumps to dry out (I try to use leather style plungers). This makes for no squirt and I have to reach for the starting fluid. It’s a pain in the ass but it just seems to be the reality if you don’t at least start them up every few days. Reading through this thread made me think of maybe putting an electric fuel pump in parallel with the stock type pump on my ‘56. But, my Austin gasser with an electric fuel pump has the same problem. After weeks of sitting it doesn’t want to start without starting fluid even though the bowls will fill up. I’m not sure what the answer is.
I’m gonna do a little test today. Both the Austin and the ‘56 have been sitting for over a month. I’m going to run the pump enough to fill the carbs and check to see if they have a normal pump shot.
If they do, I’m stumped. If not, I’ll let them sit to see if the pump seals swell up and start to work normally.
This thread has me curious as to what is really going on.


Sent from my iPad using The H.A.M.B. mobile app

 

What squirrel says above. On my 40 I have an elec pump by the tank and stock pump to the AFB. When it sits a bit I just hit a push button for a few seconds til I hear the elec pump slow down then start it up. Works fine-been this way for 10+ years.
Have done several this way.

 

Well I be live the cardboard was wet because the float levels were too high. I could also see small drips on the rear boosters. Since I've lowered the float levels ,I haven't seen that since. That's partly why i thought o had solved the problem.

 

I did my little test today. I cranked the '56 engine over until the oil pressure came up and then looked down the carb and pumped the throttle - after three pumps I got a full strong squirt. Hmmm. So I hooked up the battery and turned on the electric fuel pump on the Austin (blown SBC w/two 500 Carter AFBs) - the front carb had a full squirt after two pumps and the rear carb had a weak squirt after four pumps. So I guess that even though the gas evaporates from the bowls over time the accelerator pumps recover pretty fast once gas gets into the bowls. The '56 fired right up with just the squirts from my test, go figure, it's usually a bitch to start after sitting for a month.
I thought maybe a dried up accelerator pump plunger might have been the cause for your hard starting problem but I guess not. Like someone else said, I would swap on the carb from the other car and see if the problems still exist. If so, it may be time to replace that carburetor.

 

Thank you dickster, nice piece! Got anymore?

 

I have 2 more.