Edelbrock 1411 - 750 cfm on a 454 problem.

When I run a Q-Jet on a stock intake it runs pretty smooth and idles well. I also have a Holley Avenger that I tried on the engine with an adaptor to the stock intake and it runs well, good vacuum and stable idle. The Edlebrock 1411 used to also run well on the 454 with the adaptor plate. Now it does not idle worth a darn, pulls maybe 14" with a vacuum gauge and poor idle. I have cked for vacuum leaks and none present as I jerked off the Edelbrock and went back to the Q-Jet and it runs fine. The vacuum gauge with the Edelbrock jumps like crazy 4-6 points in a fast flutter.

Any ideas why the Edelbrock now idels poorly, vacuum jumps all over the place remembering this carb not 3 months ago ran well.

Any experience with the Edelbrocks out there?

 

I cannot get my Edelbrock to run right either. I have had it on two different cars and it runs rich. I have adjusted the floats, changed the metering rods, springs, leaner jets and still does not run right. I ordered a new carb from Summit yesterday. I just give up on it.

 

did you check and make sure the adapter plate was on correctly , I only ask cause when i got my car the PO had it on upside down a quarter of the intake was blocked ,,BUBBA runs fine now ,,

 

Cked the adaptor it feeds right into the intake correctly. Good point.

Maybe the edelbrocks are either just too lean or do not run right on bb's. I will play a little more and then maybe a craigs list canidate.

 

What did the Edel help line tech say?

 

How did you check for vacuum leaks?

God bless, Sensei

 

The tech line was busy this week when I tried, am calling again today. Cking for vaccum leaks was to pinch off each hose to the carb and the intake feeds while monitoring the vacuum gauge on the intake manifold. No appreciable change. Thanks for the suggestions.

 

It's possible that if you just yanked the carb off and set it aside that the gas in it has evaporated and left varnish deposits behind in all those tiny, tiny passages that meter fuel and air. The gasoline we're getting nowadays is the pits!

 

That makes a lot of sense about varnish from today's high priced junk. Here is Illinois we have the double wammy of etheol and oxygenated gas that has caused problems. I did pull if off about 4 months ago and it has been on the shelf. I reinstalled it and that is where I ran into the problem. Do you think running it and squirtting it with carb cleaner and some time would clean out the ports if they are plugged up??

Recently, I had a gas leak from the "S" hose from the tank line to the fuel pump. When I pulled it I was shocked. The runner was literally cracked and eaten through. That is a lesson for the wise.
JP

 

You need to do more to test for vacuum leaks, as that sounds like the problem and what you did was not complete. A few years ago I found a guy's vacuum leak on an Edelbrock carb where a factory plug had just fallen out of the carb. Here are some suggestions:

As the engine idles:

1. Spray carb cleaner around the base of the carb. If rpms increase when you hit a certain area, you have a leak there.

2. Take a peice of 1/4" vacuum hose about 2' long and put one end in your ear. Use the other end to listen all around the carb. You will hear the air if you get near a leak.

3. I don't care for this one too much, but some people hold a lit cigarette near the carb and watch the smoke to check for leaks.

God bless, Sensei

 

Sensei, I will test for vacuum leaks the way suggested, other than the cig for a test. Somehow sparks and gasoline do not mix.

The issue of a plug out might be a possibility and using carb cleaner while it idles also. It certaining does sound like a leak and I will get to it on Thursday and let you know. Thx

JP

 

I have absolutely NO practical experience with Edelbrock carbs. Someone who has can offer advise.

However, after replacing 3 carbs on air-cooled engines clogged with, and for want of a better term, varnish, left behind because of my failure to run them dry before storage or to run Stabil treated gas through them, I wasted my time and $$$ on carb cleaner and rebuild kits. They were for Husquvarna chainsaw, Stihl brush cutter and Onan standby generator. Each used the same name brand of gas as my '02 pickup truck.

When I asked the owner of a small engine dealership why this same gas works fine in my fuel injected engine he had this advise: the passages are so small in carbs that carb cleaner cannot get in there to soak out the varnish, mostly because surface tension won't let it. It'll make the parts you see all bright and shiny but will not affect those tiny air bleed and fuel passageways.

Once they are contaminated, they are junk. He said even he couldn't resurrect them. Carbs are temperamental that way.

This is what he does to prevent our crappy gas from causing problems for his business:

He has an underground tank and only fills it with premium grade gasoline. He immediately treats it with Stabil. He does not store it for more than 1 year. Any remaining gets pumped into his fuel injected service vehicles. Any engine that sees only intermittent use should be run dry before storage.

I paid the $$$ for new carbs and follow his advise religiously. So far, so good.

I see no reason that the basic operation of an air-cooled carb would be any different than water cooled.

Perhaps someone with greater experience will chime in.

 

A small engine carb is a very simple and relatively inexpensive (especially dealer cost) part. They can be made to work, but no repair shop would take the time when a new carb is so cheap and easy.

An automotive carb is worth taking the time to clean out. I soak them for at least a day fully submerged in laquer thinner (carb cleaner). I then blow compressed air through all passages (wear eye protection). Even with that, I did have a guy's numbers matching big block Quadrajet once that wanted to stumble from weak pump shot. I ended up blowing a very thin peice of monofilament (fishing line) through that right side pump passage, then tied a peice of thread to the line and pulled it back and forth through the passage to clean it out. That worked, but try to find a mechanic these days willing to go to that kind of trouble to fix something rather than replace it.

God bless, Sensei

 

I think the basis of the posts by 69 chevy and sensei are right on and the source of my problems and probably lots of other guys on the forum. A car sits for months, gas evaporates and the varnish remains in the little tubes. Startup comes and wow, runs poor.

I have used Stabil for the tiller and snow blower and mower but not in the car at winter time.

Question - how does Stabil prevent varnish from forming? I thought it prevented the old term "soured", which I bet is lost octane and varnish.

Edelbroch tech lines are perpetually busy, but I bet the information they have will be no more valuable than what has been posted. I will try again at a different time to see what they say.

thanks people for the top notch information and time to post.
JP

 

Check your fuel pressure. Had problem with Edelbrock that would die sometimes at idle and sometimes stumble on hard acceleration. Found my fuel pressure at idle was between 8 & 9 psi. Edelbrock recommends max of 6. Put on a regulator and no further problems.

 

Question on fuel pressure. What pressure can you expect from a stock carter fuel pump? The Q-Jet seems to run fine and not shoot from the squirters indicating too high a pressure. I can see though Edelbrocks may be more sensitive to pressures. I will look into getting a pressure regulator and guage to make sure I do not have too much pressure. Thanks for the input.

JP

 

If it's a Carter electric fuel pump, I get 7-8 psi from mine measured just before the float bowls.

 

Well, I'm no dealer, so didn't get any price break at all. Just the Stihl carb would have cost more than $100. And I priced all over the net plus a few local dealers. I couldn't justify that price for a tool over 20 years old, so junked it and bought a new brush cutter. Both the Husqvarna and Onan cost even more. I guess 'relatively inexpensive' is a subjective term. For me, leaving gas sit so long that it evaporated inside these carbs was a VERY expensive lesson to learn.

 

I feel your pain. The point I was making is, that $100 retail carb probably cost the dealer $50-$75. They often charge $40+/ hr labor, so they just do not want to take the time to soak, blow out, re-soak..., then rebulid and hope it works right when they can just bolt on a part.

God bless, Sensei

P.S. Yes, you should not let untreated gas set in the carb in the first place

 

The AFB series of carbs have the jets right at the bottom of the carb. They are prone to getting crap in them. A great fuel filter is a must with these carbs as I've seen junk get through poor quality filters and bugger these up. Even build-up from fuel additives will do it sometimes if the carb has sat. I'm betting you probably have some foreign material that has made it's way into a jet and is plugging up one of the fuel circuits. They also tend to stick the metering rods if the piece is big enough.

If you don't find any vaccum leaks take the carb apart and clean it real good; especially the fuel passages. Another thing with 750 AFB's, they were usually jetted pig rich from the manufacturer. I've had to jet them down as much as five sizes to get the a/f ratio right; but I'm at 5000' too.