camarocasanova

iTrader: (1)

Here's the story: new vortec crate motor, performer rpm manifold, hei with vacuum advance, and a 1406 edelbrock powered by an external fuel pump. Car starts great no problem when cold. When hot, sometimes it fires right up, most of the time it gurgles and blows a bit of smoke from under the hood. Holding the starter longer doesn't seem to solve. But holding the pedal to the floor will get it to start. I think it is flooding the carb.

So far I have installed a phenolic spacer, a holley fuel pressure regulator dialed all the way down to 4.5 psi, and a new fuel filter among other things. I took the top of the carb off and re-set the floats. I have played with timing, jetting, etc. NO change. I am out of bullets here. Any ideas anyone?

JTS

When I bought my edelbrock for a 350 build I did many years ago, the primary metering rods and the plungers were missing from the carb. The engine would start but not run very well at all....sorry I missed the part where you had the top off of the carb.

eseibel67

Is the choke coming off?

InfernalVortex

iTrader: (4)

Carb might be just getting hot and the fuel is vaporizing somewhere in the system.

I had a problem with it for a long time prompting me to do a lot of research, and the one common thing I saw was that no amount of insulation and phenolic spacers ever seemed to actually fix the problem even though theoretically they should. Look into it on google... carb heat soak. It seems to be becoming a bigger and bigger problem.

In my case the fuel in the carb that gets too hot just evaporates out of the vent tubes, no problem. but the fuel that's in the feed lines cant vent, so the fuel that vaporizes in the feed lines just collects at the highest point - the needle/seat assembly. As soon as the line gets pressurized the gas blows straight through, into the carb, and pushes out a bunch of gas through teh vent tubes as it makes its way out. Gas spills into the venturis, floods the car, requiring a WOT cranking to clear it out. Car runs like crap after 5-8 seconds of cranking and there's black fuel smoke out the back for a second...

https://www.thirdgen.org/forums/carb...-restarts.html

That's my thread about it with some trial and error and hypothesizing.

If this is what is happening to you, go ahead and open the hood when it's hot out and you expect it to happen. Pull the air cleaner. And crank, and see if you see geysers of fuel spewing out your bowl vents. I get as much as a 3-9 inch geyser of fuel out of one or both my holley's bowl vents and usually it goes straight into the engine. Its very obvious what's going on after you see it happen. If it of course, does nothing unusual visually AND still acts up, then you can at least rule out a boiling/vaporized fuel issue.

I have my fuel pump on a switch so I can cycle it on and off in these situations. Since I can cycle it, I can prevent ALL the vapor from spewing through the carb at once. I can spew it through a little at a time so it just harmlessly vents without pushing a bunch of fuel out with it.

The other solution, my clever buddy came up with this, was he got a vacuum line, put a few holes in the top of it, and put it into two spark plug boots. Both boots went on a bowl vent, and the holes in the crossover line were the new vents. It boiled over that time and didnt manage to spill into the engine. Just giving it more crap to go through slows it down enough that it doesnt spew out liquid.

The 4x4 models of Holley carbs have special vent tubes that connect and have holes drilled in the top. I think approximating that design with some tubing would be the best solution.

'84thunder

in my experience, edelbrock carbs are junk. anything that is chrome and deals with fuel, is poopoo. i had an edelbrock carb 1406 (same as urs) on my camaro and it was junk. the choke didnt wanna work right, the idle bolt kept loosening on it self and never stayed put, the throttle cable and kick down cable were in each others way so that was a mess.

the other thing is, a carb'd motor will always start right up with no problems when they are cold, however you need to keep ur foot on gas pedal and keep RPMs up to warm up the block (so choke will come off) these motors HATE...HATE being started hot or warmed up. as for your smoking problem, someone up there in the comments had mentioned the fuel was vaporizing and it was basically the steam or smoke from that. could be, i dunno.

if i were you, i would get that edelbrock junk off ur motor and grab a holley double pumper or holley anything. you can find them used on craigslist or new on summit or jegs.

remember...this was just my

TreeFiddy

Mine starts up fine hot or cold, but needs a bit of boot for the first minute when dead cold to warm up enough to idle. That's what the fast idle cam is supposed to be for. That I don't have.

'84thunder

well, i have driven alot of carb'd motors and 90% of them hate being started when warmed or hot. maybe urs is in the 10%? im just speakin from my experience. i understand bout the high idle cam and having to keep the throttle on to warm the block up. i live in central NY and its cold as hell here and every day i start her up, i have to keep her runnin a lil bit.

Ozz1967

iTrader: (4)

I've got a Qjet on mine, got the choke set and never had an issue with it through the Utah winter last year. Runs fine when warm as well, never had a problem starting a "hot" motor.

To the original poster, do you have the return line hooked up? Also, what is your fuel pressure set to? It should be set to no more than 5.5-6psi for that.

'84thunder

well i have a POS (piece of ****) edelbrock, soon to be replaced by a holley. maybe mine starts rough on hot motor because it has aftermarket crap. i know where your coming from, but i have seen some shitty carbs an engines and they just dont like hot starts.

Ozz1967

iTrader: (4)

LOL< your opinion of the Edelbrock seems to be the consensus here on the boards. I'm sorry you're having such issues. Try the steps previously posted and see if that gets you anywhere.

'84thunder

nope. just gonna replace the poopy carb with a better one. but thanks for ur advise

cal30_sniper

iTrader: (16)

They've always worked fine for me. If you're having trouble with it starting, or running, then you've got something set up or tuned wrong, plain and simple (that, or you're using a carb that's old/dirty and needs a rebuild). Remember that the Performer is simply an update of the tried and true Carter AFB design (which was used on a whole bunch of vehicles as factory equipment). If the factory got it right, and a lot of other people are getting it right, there's about a 99% chance that your problem is related to operator error.

To the OP, my advice is to stick with the Edelbrock carb and figure out what isn't set right. They are a good design, and more economical/easier to tune than ANY Holley I've ever messed with. How old is the carb, what kind of condition is it in, and has someone else owned it before you? If it's a used carb, check to make sure the primary jets and rods are what it came with from the factory. I'm going to bet that your problem lies in the choke adjustment, that's where almost all of your startup problems come from. Sounds like your choke is set up slightly on the rich side, and needs to come off just a bit. With a properly set up carb, you should be able to pump the pedal once, hit the ignition, and let the carburetor do the rest. You shouldn't have to sit there and warm up the engine, that's what the choke is designed to do.

cal30_sniper

iTrader: (16)

You must be driving a lot of badly tuned carburetors then...

camarocasanova

iTrader: (1)

Ok to answer some questions that have come up:


The Carb is brand new. It has no return lines.

I am sure it is still flooding and what InfernalVortex is saying sounds interesting and plausible to me considering what it is doing. I am not going to give up on the edelbrock, I just need to get smarter.

five7kid

iTrader: (14)

If you are running an in-tank electric fuel pump, you need to use a regulator with a return line.

So, what fuel pump are you running? I scanned through this thread sort of quickly and didn't see.

TreeFiddy

In my previous experience, bad hot starts with a carb are usually caused by a vapor lock, or the bowls evaporating dry in the time the motor was sitting. Until I got this car.

From your description of how flooring it will get it to start, it does sound like a flood. Reading Infernal's research leading to his 'geyser' theory makes sense to me, as it was happening to me too on occasion and I made the same observations, although to a lesser extent.

Don't know if the Edelbrock has the same arrangement of bowl vents to connect or cause problems like a Holley does, but in my case the problem was caused by bad fuel hose routing. I had the fuel hose crossing over in front of the motor, hanging down into the hot air flow exitting the fans.

I moved it up a couple of inches, and the bad behaviour disappeared; that was several months ago, it's mid summer here now and no sign of it returning. You presumably have altered fuel hosing, maybe this is affecting you too.

Edit: Actually after thinking a little more, this probably won't be your problem. I had no problem starting; the flood would occur about 30 secs after starting. Your fans of course aren't running prior to the start attempt, to be involved in the no-start.

camarocasanova

iTrader: (1)

It has an external fuel pump that is cut inline just outside of the gas tank. It is one I bought from summit, it isn't a major name brand though.

Ozz1967

iTrader: (4)

InfernalVortex

iTrader: (4)

I cant imagine the air coming off the radiator is hotter than the air over the engine... The time lag between when I hit my switch and my car flooded over wouldn't be 30 seconds... but it might be 5. It wasnt immediate but it just needed time for the fuel line to pressurize.

Id have to see how you run your lines I guess. I'd be inclined to think that whatever you did changed some other parameter of its function. There are guys who run fuel lines next to and around their header primaries and dont have this problem, and tahts got to be WAY hotter than radiator exhaust air. Is the fuel line where you raised it perhaps one of the highest points in the line for a few feet in either direction? Is it giving gaseous fuel (vaporized) a high point to collect in away from the fuel bowl needle/seat assemblies?

The better I understand why some people dont have problems and some people do the better I will understand exactly what's going on. It's just odd because some people can have very similar setups to me and NEVER have a single problem. And others cant get away from it no matter what they try. Something you've done has worked, and I want to know exactly why it worked.

Where is your fuel pump? Your regulator? How are your lines routed? What feed lines are you using?

TreeFiddy

Hi Infernal - yep I agree it's unlikely but it's the only 'go figure' theory I've got as to why the hose re-route worked. Mine is a 350/carb swap from a 305/TPI - parts list:

Tank - original 86 TPI tank afaik. Internal setup unknown, never had it out.
Pump - external low pressure pump similar to this: http://www.summitracing.com/parts/PFS-10700/
mounted on rear bulkhead behind the back seat, below and in front of the tank, approx where the factory TPI fuel filter would have been I presume.
Lines - factory TPI, cut at front chassis rail, then rubber fuel hose.
Filter - cheap plastic pos.
No regulator or functional return line.
No headers, just factory manifolds.

This is how the po had it set up.

Moving the fuel line out of the fan air is the best guess I've got as to why it stopped flooding, in conjunction with your geyser theory. I agree that the manifold/exhaust air should be the hotter of the two, but it worked.

Probably the location of my fuel filter has something to do with it, as you can see in the pic. It does end up at the high point now, in the current working configuration.

The system behaves itself perfectly as pictured, but will flood the rear barrels on hot day hot starts via the bowl vent after about 30 sec, if I drop the fuel hose and filter below the rad top hose.

InfernalVortex

iTrader: (4)

Now I REALLY wonder if you now have vaporized fuel or fuel components in that filter which would actually support my current hypothesis. I wish there was some way to test it, though. For my setup due to my Performer RPM intake and my Holleys, the feed line is a good bit lower than my carb. So any vapor that can will head straight up to the carb itself....

Since your pump is way back at the tank with no regulator... the 30 seconds makes more sense. That may be the amount of time it takes for pressure from the pump to actually get to the carb.

TreeFiddy

Well, I can confirm that there is usually a bubble of vapour trapped in the filter at the top while operating.

When the fuel line was lower, I used to have a lot of problems with what I thought was vapour lock on hot days. This would usually appear as surging, but could happen at any time while driving, not just at or immediately after startup.

I fixed that years ago by isolating the metal fuel line with a heat shield that I fabbed up, where it ran past the exhaust. This is what convinced me that I had in fact solved a vapour-lock condition, but it did leave me just with the surge after startup that we have be talking about. It wasn't something that happened every time, and only on hot days, so I always put it down to some artifact of vapour-lock.

When I bought my car, it was a basket case of chronic overheating, vapour-lock like surging, and outright quitting after about 20-30 minutes driving on hot days. After solving all this, the occasional dip after startup was something I could live with and just got used to predicting and working around.

This little blip aside, it has run fine for years. Interestingly enough, the filter has always had the bubble in it, sometimes to the point where the filter is more full of vapour than actual fuel, but it continued to run fine. Sometimes I couldn't see how it was even running, but there it was.

Also interestingly, after the last cam swap a couple of years back, the fuel line heat shield became unnecessary. I never put it back on after putting the top end back together, and the vapour-lock never returned.

Several months ago, I had the carb off several times to remove crap from a disintegrating hose. The last time I accidentally put the fuel hose back on routed above the top rad hose, rather than it's 'traditional' position below it. Which led to the immediate disappearance of the hot-start shimmies, and the traditional 'wetting of the carb' above the secondary venturis.

Whether my problem was the precisely the same as yours, or have the same cause, I don't know. When I tripped upon this thread and subsequently your other one, I felt a sense of sympatico, the symptoms seemed to broadly match.

danielsan

Probably a bad tune. You say there is steam "or smoke", which could also be not running the engine hot enough to vaporize all the fuel which is bad for everything.

Check the plugs and see how they look. My guess is you're running too rich. My car right now is running a bit rich - on a cold start it runs fine until it warms up, and then it bogs a bit on throttle. But I'm doing a carb rebuild / tune up next week. Check the timing and redo your air/fuel mixture.

305sbc

iTrader: (3)

Ok you've got a crate motor and Edelbrock carb.
Now besides the vapor build-up in the fuel line theory itself, could it be that your fuel vapor canister isn't hooked up and functioning the same way as it used to in order to release pressure from your fuel tank?
After sitting off for 10 minutes hot, - same situation which would cause your flooding, then without attempting to start the engine test the pressure in your fuel tank by removing the gas cap slowly.
If no audible pressure release, then no problem there.

One other possibility is your spark advance.
More than around 10* initial will start great cold, but will have problems once the engine is hot. The engine may crank slower and it might spit back up through the carburetor when first started. If an intake or exhaust valve is not sealing good enough you can get the same spit-up like that.

If your initial is 10* or less, then here's a simple test to rule out spark advance being part of the problem. Plug off the vacuum supply to your distributor's vacuum advance and observe if there is any difference in your hot starting.

Ronnie Brennan

I've had a number of carb'd cars and all had edelbrock on them. I've never once had any problems with them. Anyone that is not had a lot of experience with carbs and can handle tuning them all the time are free to buy you holley's I am a fan of Edelbrock because they are very user friendly. You put it on your car and you drive away. It rarely needs tuned. I've had my Edlebrock 650 on my camaro for 5 years and live in Canada, so we have some hot and some very gold days, I only once had the car not start properly and smoke after a start because I had it out on the highway with my camaro club with all of us hitting 150-170 km/h and since I am normally a 90km/h driver with my camaro I suspect that holding the car at WOT for as long as I had and the throttle had stuck open due to not being used as hard as that for "ever" never has happened again.

Ronnie Brennan

In lieu of some of the comments being made...... There sure is a lot of hate for Edelbrock carbs on TGO..... Considering that almost everyone here and his dog has one

five7kid

iTrader: (14)

I suggest a recount. Look in the carb'd photos stickies and count the number of Edelbrocks vs. Holleys vs. q-jets.

I would concede, though, that there are more threads about problems with Edelbrocks than there are threads about problems with Holleys. Hmmm, wonder why that would be...

rusty vango

todays alcohol fuel is the problem id say if you got a load of ,say AVGAS or sunoco or any pure gasoline.you may find your problem gone. and most people i know running carbs are having similar problems with it ,including myself (68 dodge work van) another heart warming thing is this;alcohol is corrosive by nature.im getting more and more fuel tank/pump repairs lately and im noticing that the insides of older metal tanks are being eaten ,sending units are corroded.fuel lines too.before "corngas" this wasnt a issue

305sbc

iTrader: (3)

I can also vouch for Ethanol being a definite source of problems for an aluminum carburetor like the Carter/Edelbrock models.
Even though the passageways in the carb are mostly lined with thin brass tubes, they are surrounded by unprotected aluminum, and so corrosion will grow on the insides of the passageways such as the air-bleeds in particular.

Aluminum carburetors have always had an issue with wicking heat to and from sources at a very fast rate. This can work to your advantage in certain situations, but it can cause problems in other situations. The aluminum carburetor body is responsible for increased instances of both icing and heat related problems such as vapor lock. Both problems have been compounded greatly in recent years by the addition of Ethanol to our fuel.
The main deciding factor in this process is that the boiling point of Ethanol is just 172*F. The increased rate of flash-vaporization for Ethanol is responsible for both vapor-lock occurrences, and more icing up around the throttle blades.

This is another strike against Ethanol along with its tendency to corrode and poorer fuel efficiency.
There are instances such as WOT operation with high charge temps or high cylinder pressures where Ethanol really shines as a fuel, but normal driving under varied environmental conditions is not one of those instances.

In the same sense, aluminum carburetors can really shine in performance applications, but do tend to have more issues with normal driving in widely varying environmental conditions.
I still like and prefer aluminum carburetors, but I realize that certain steps must be taken to avoid issues due to quick heat wicking, and with corrosive additives in the fuel.

As an added note, the corrosion due to Ethanol tends to create the most problems when the vehicle isn't driven on a regular basis. Sitting stored with fuel in the carburetor is the worst thing you can do, and almost guarantees that you'll have carburetor related problems.