Rockable and the guys suggesting 4lbs of fuel pressure are the big winners here! I too have messed with the Edelbrock that came on the 'Bucket, that was horribly mistreated at some point in it's life. I think I finally have it naild down after flush tons of silt and crap out of every passage. But first thing every time with these carbs is no more than 4lbs of pressure. I actually run 3.5 on mine these days. Please don't think that pressure = volume, either. A good quality pump will deal with volume just fine, keeping the pressure below the point that overcome the needles and seats is the key. The other thing to think about, is if you HAVE to run ethanol fuels, the normal boiling point of regular gasoline is reduced by tons when the ethanol is added. Like down to what we carbureted guys think of as "regular running temp"... Adding an isolated spacer to help keep some of that heat out of the carb is a damn good thing.
Edelbrock's off road needle and seat solve a lot of fuel related problems. I install them in every new carb before I even see a problem. It's spring loaded for the off road bouncing guys. More resistant to variable fuel pressures.
Latest in the saga: Rebuilt the Holley and it does the same thing right from first startup. Reduced the fuel pressure to 3 lbs with no improvement Installed a new electric pump with no improvement.
Is your tank vented ? Did you put a non vented filler cap on the tank? Try taking the cap off and running the car. Also I vote for 3psi. Nick
Fuel pressure is fuel pressure, that's it. I like to run just enough not up to what the needle and seat can handle. So you now have 400 trouble free miles then 3 carbs and two pumps giving the same results. If you are certain ( I'm not ) that its fuel related, look at the source of fuel (tank) and the lines delivering it. Have you checked your coil and wiring to it? Made sure the current flow is sufficient at operating temps ? The ignition system in general?
At this point I'm starting to lean towards the heat soak theory, whether carb or ignition. Can you actually see fuel dribbling from boosters at idle when this occurs or is it only happening at speed? Seems like you also mentioned it being flooded after sitting and this would tend to confirm. Also, any chance the temp gauge is off and it's running hot?
See post #29. Today's gasohol has a lower boiling point. You need that insulator between the intake and the carb. I had to put one on all my vehicles with carbs.
I thought I had a flooding problem with my edelbrock carb. The plugs were wet with gas. Running rough and stalling. It turned out to be a weak spark from a failing condenser. Replaced the condenser and now it runs great again. I have a Holley red fuel pump without regulator. Running about 5 1/2 psi fuel pressure.
I second the condenser deal… most are now made off shore and I have seen many that are bad right from the start. I'd sooner use a 30 year old condenser from a junkyard than a new Chi-Com part. You should also check that coil...
I've run the 1405 on my SBC 350 for about 18,000 miles with no problems at all. I have a mechanical fuel pump and after reading all the fuel pressure numbers here I'm wondering what pressure the mechanical pumps run at. ???????
On mine,I ran into similar problems.kept cleaning the junk out of the carb,(new fuel lines,perfectly clean tank) Changed to a mech pump with about 6psi at the gauge....same. Installed phenolic spacer....same. Finally insulated the new fuel lines where they ran along inside the frame near the headers,and the running problems went away! I believe the junk was coming from residue from what was left after the fuel boiled dry. The plastic split tubing covering the wiring for the head/turn lights on the drivers side showed some melting also,so that got insulated too. The carb probably still boils dry or evaporates after shut off as it takes a while to crank fuel to the carb when left for a week or so
I mentioned that the Edelbrock that came on my 'Bucket was heavily abused when it came to my hands. 'Matter of fact, the guy that sold me the carb told me to toss it. It was packed with silt and just general garbage that is common to the Southwest. One thing that Landseaandair just said made me think... When I finally got this thing working, I was still seeing a dribble of fuel from the primary boosters at idle, even with the pressure regulator and razor sharp float height tune, both up and down. Reluctantly I pulled the carb back apart, removed all the boosters and idle needles, and started round 13 of blowing carb cleaner and compressed air though EVERYTHING. When I got to shooting carb cleaner through the idle needle holes, I slightly opened the butterflys, and noticed that I wasn't getting even amounts out of the transfer slots. Blew cleaner back through the slot from the butterfly side, and out of the needle hole popped a chunk of crud the size of my Shih-Tzu... Point is, I had blown though this whole side of the well 13 times before and managed to miss this chunk. I only found it when I slowed down and checked EVERY function of the carb very methodically, and then reversed what had at that point become "standard procedure". After that, no more dripping, adjustment was restored at the idle screws, the idle settled down, all was well.
Double checked the float levels on the Holley. Wired the pump to a second battery. Same results. Note also that with the Holley there is no period of "good running". It begins to stumble immediately after starting and shuts off within a minute unless the pump is turned off. So heat is not the culprit here. I really appreciate all you guys' suggestions on this. Since there's no way I can keep the thing running long enough to see what's happening inside the carb, tomorrow I'm going to put the carb and the pump on the bench and run some fuel into it.
Ive had this happen twice over the years. Everything pointed to fuel but we found it while just guessing and changing out parts the first time.
Run the engine off a gravity fed gas can. Right from the gas can to carb using a short piece of new gas line.....this will rule out the gas tank, gas cap or vent, fuel line, fuel filter, fuel pump, pressure regulator. Good luck!
Since all the evidence mostly suggests a fuel problem, couple more questions. Always using the same gauge? Any chance the pressure is creeping slowly? Regulators can fail from debris just like a needle and seat. If all else fails, a pic or two might help.
Turning off the fuel pump when the miss started, caused the engine to clear and run smoothly until it began to run out of fuel. Restarting the fuel pump would bring the motor back to smooth operation for about 5-10 seconds and then the miss would resume. Turning off the fuel pump again repeats the process. Have you explored this yet. This will be real easy and free. Worth getting this off the table A miss is usually electrical or ignition (spark) related when carbs are being used. You have random misfire and localized. Randoms are almost always in the electrical components of the ignition. Coil condenser points or module. Localized misfire can be a bad cap, wire, plug. The localized can be mechanically caused by lack of compression in that cylinder. Fuel problems stemming from carbs are no start, loading up, lean coughs backfires, rich exhaust. Reading plugs get you pointed in the right direction. Fuel delivery problems can be anything that touches the fuel from the tank to carb inlet. Vents, hot lines, heat soaked carbs, filteres pumps tank, hoses, connections. It's very important to establish that every component gets its required input. Voltage, pressure, signal. Once you know that you can determine with parts are bad by monitoring the output. Easy peazy. Otherwise you spend lots of time and money changing parts fixing nothing and learning how wrenches work.
1405/1406 tend to like 3.5-4.5psi on just about any small block i've seen them atop. and for gods sake whatever you do don't do like most and trust the marketed "my pump says ___psi" they are wrong about 70% of the time. i've also seen a bunch of low end regulators that were about as useless as could be. but back to an earlier response. i was doing some traveling for work 5-6 years ago in sc in my 64 vw. it came with these same symptoms. well suck on the hwy between rock hill and columbia i rebuilt the carb, changed plugs and wires, set points, changed the coil. all in about 10 mile sperts. finally got to columbia and found out it was a bad condensor and had it fixed in 5 minutes after being roadside fixing all the others for about 5 hours in july in south carolina....
I Had the same problem with an Eddie 500cfm{1403}. I knew it wasn't points because I run a Pertronics unit. I ended up pulling the dizzy and adjusting the up and down play in the shaft. The trigger wheel would move up and down away from the magnetic pick up. After that my "fuel" troubles disapeared.
Put the new 1406 on the bench with the original JEGS pump and a can of gas. Started the pump and fuel ran out of the inlet side vent. When I pulled it apart I found the float filled with fuel - defective right from the factory. The pin hole must be so small it let me drive 60+ miles before it filled enough to flood the engine; anyway its too small for me to see. I have new floats on order along with the off-road valves and seats models916 suggested. Haven't yet tested the other 2 carbs but can't believe they'll show the same problem. The odds seem too great.
Can't argue with Big-Foot. Maybe it was always there and I was too dumb to see it until it got so full I felt the weight. New float will say yes or no to problem solved for this one. Will keep working on the other two. Thanks again for all the help and ideas.
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