Carb, I think, question

[phat46]

I believe I'm having a carb problem, the carb in question is an Edelbrock. Everything seemed fine when I ran it a few days ago, Idled fine, no stumble when revved, etc.  Today the engine is dying when it gets warmed up, simply won't run unless it's held to a fast idles speed and even then stalls when I put it in gear. I did wire up the electric choke on it today, but it does it with the choke unhooked too. Is it possible that the idle curcuit has plugged? I checked for vacumn leaks and have eliminated any possibilities there. Any ideas?

[enjenjo]

I just went through a similar problem with a Carter carb, It was a missing vacuum cap on one of the unused emission ports. Such a big leak it was hard to find.

[river1]

I just went through a similar problem with a Carter carb, It was a missing vacuum cap on one of the unused emission ports. Such a big leak it was hard to find.

your concorde???

[phat46]

I just went through a similar problem with a Carter carb, It was a missing vacuum cap on one of the unused emission ports. Such a big leak it was hard to find.

Frank, that was one of my first thoughts too, It was missing a cap on a port that I found  a week ago, it wasn't running too well before that and after i replaced that cap it ran better than it ever has.  I really checked it over good today and i can see no vac leaks, I took out the vacumn "tree" that used to have four ports on it for the power brakes and trans etc. and plugged it with a brass pipe plug....made no difference...

[C9]

Does it run rough even when warmed up?

And clear out when you give it some gas?

You may have a metering rod stuck in the up position if it really runs rough.
If it runs not too rough the metering rod is only a little ways up.
(You probably know it, but vacuum pulls them down and the springs hold them up.)


Pull the rods and see if one of them is bent.
Easy to do, unclip the piston and spring & roll the metering rod on a known to be flat surface - with the short leg hanging off the side of your surface plate or whatever you use.
A thick piece of glass, flat piece of steel or even the kitchen formica works for this.

Use care when straightening them, it's easy to go too far the other way.

I had a pair of Carter 500's on my Buick engine.  (Same carb as the Carter, they both come off the Weber assembly line.)
They ran well at the start and one day a metering rod hung up which made it run rough.
You'd think something like this should happen right at the first, but if the bend is mild the rods may work fine for a while.

[C9]

The age of your carb may make a difference as well.
I've seen the rubber caps split open after only a few years.

Most any parts house and even Pep Boys and their ilk carry plastic caps in one bag in assorted sizes.
I have a set on my carbs and 10 years later the plastic caps are still doing fine.

I'm wondering if a ruptured vacuum advance can can leak enough air to make the engine run bad?
Most leaks in these are pinhole type leaks, but you could shoot the timing with and without the vac can hooked up and see what you get.

Running points?
Some of the plastic rubbing blocks don't last long, specially without lubricant.
Check the gap, the points may be almost closed.
Gap should be 014-016 or so.
That's with the point rubbing block on the high point of the distributor cam.

The fiber rubbing block points last a long while.
Especially if you toss the lube that comes with them and get a tube of genuine Points Lube Grease.
Less than $5. probably.
One tube is a liftime supply.

A closed up set of points acts very much like a carburetor problem.

[BFS57]

Hello!
Like you, I had the some of your exact same problems!!! I faught it and faught it!
1. Check the float levels
2. As allready stated, check the metering rods
3. Check the needle and seats to insure they are properly seating.
4. make sure you are not puting too much fuel pressure to the inlet.
5. As stated check for leaks in the vacume lines and plugs.
6. My carb had to be set with a vacume guage. Once I did this for maximun vacume at idle (warmed up) I lost several "problems I was having from being too lean!
I went as far as to completely re-route my fuel supply line and insulate it with a piece of rubber hose over the metal fuel line.
I still have problems which I now think are related to my distributor and secondary wiring. That is next on my list of things to change!!
I also purchased a Edelbrock Tuning kit which I have found very helpfull. I got this from our local Autozone. Be carefull, you may need to take a magnifyer to make sure that all the metering rods and jets are correct for the kit. I had to look through a couple kits to make mine correct! The numbers are very tiny. I use a jewler's eye loop to see these. (My eyes arn't worth a hoot anyway! And don't forget the Edelbrock manual! I have found this really helpfull when I need to make adjustments!
Bruce

[phat46]

No points, Ford Duraspark/G.M. module combo ignition, all the rubber caps are good, or eliminated, still scratching my head as to why it went from running good to this in two days, without running it at all btween the good and bad...

[BFS57]

Hello, Again!
How old is this Carberator? Have you had it apart? You may have dirt problems! Also, check to see if one of the floats is sticking!
Just a couple of thaughts

Bruce

[phat46]

Hello, Again!
How old is this Carberator? Have you had it apart? You may have dirt problems! Also, check to see if one of the floats is sticking!
Just a couple of thaughts

Bruce

I don't really know the age of the carb, it was on a good running engine I got for a project; I never took it off that engine; I've never had it apart, it did sit for a while before I started the engine, but it started and ran well.  The fuel tank I built myself with clean metal and there's filter on the fuel line....
Doesn't seem to be flooding, rather  it seems like it is starving at idle, if i hold the revs up it will stay running.

[EMSjunkie]

Wanna trade for a Holley  

she runs fine, off idle.  at idle she runs fine, just gasses you
out of the shop after about 1-2 minutes  :x


Vance

[C9]

Any chance you've introduced water laden gasoline into the tank?

[phat46]

Wanna trade for a Holley  

she runs fine, off idle.  at idle she runs fine, just gasses you
out of the shop after about 1-2 minutes  :x


Nope, I got one of those too, on my '46, I put in a big cam and it ran like crap till i drilled a couple small holes in the butterflies, now it runs O.K. but still rich at idle, but who idles!!!??  

[40_Tudor]

Having the same problem with a friends 37 Chevy with a 350. Made it to Goodyguys Friday but couldn't get it back Sat or Sun because it ran so bad.
Take the air cleaner off.
Start your car and cover most of the carb with your hand, and see if it runs better. You can also close the choke butterfly most of the way.
If the engine runs better, you have a vacuum leak.
The friends 37 has a 350 with the heads milled .030 and the blocked decked. I tried a new carb, added a plate the base, He had a spread bore intake with a square bore carb. Didn't help. Blocked off all vacuum ports. Cussed a lot.  :evil:  :evil:  :evil:  :evil:
Finally pulled the intake and notice oil on the bottom half of the Felpro intake gaskets.
Too much was milled off heads and intake gasket was sucking lots of air internally. Couldn't hear any vacuum leaks outside. Ran good as log as the choke was on or above 2000 rpm.
Maybe you'r engine sucked an intake gasket.
Check everything else before you pull the intake.

[EMSjunkie]

x

 now it runs O.K. but still rich at idle, but who idles!!!??  

I like the way you think    


Vance