Edelbrock/Weber on a 1969 390 crappy idle when its hot out
 

Have a rig with a 69 390, has an almost new Edelbrock/Weber 4bbl..

Runs great... Starts fine... Engine is fresh...

Usually idles great..

then all of the sudden, even before the engine gets hot, it has a crappy, lumpy, almost stalling kinda idle.. SOmetimes it does stall.. Better last winter, but not positive its heat related.. Changed the fuel lines to rubber and moved off the manifold.. Has a nice Edelbrock manifold..

HELP!!!:-huh

I'm not the one to answer your question, but I just typed in Edelbrock on the net , there are pages and pages of Edelbrock carb info that may be of help to you, while you wait for someone to chime in. Could an electric choke be masking a problem, and then stopping when it opens up? Like I said, I'm not a carb expert. Best of luck. (Google Edelbrock carb trouble shooting?)

I had a similar problem with my 69 Galaxies 390. A friend gave me a phenolic carb spacer to try. His theory was, the gas was getting too hot and boiling in the bowl, which leaned the mixture out.
It seemed logical, so I tested the theory by unhooking the electric choke's coil and operated it manually while the engine was acting up. Closed the choke partially, and the idle smoothed out somewhat. Good enough. I put the phenolic spacer in, and never had another issue with it.

This link may help.

I also have a spacer between my Edel. carb and manifold, and have had no problems with heat either.

Does it have an automatic choke ?
If it does , has the idle been adjusted correctly for when the choke is off .
Also check idle mixture with the choke off and engine warm .

I did pull the air cleaner and visually inspect while it was stumbling,,

The electric choke was fully open..

It does have a spacer, but im not sure what its made of, ill check

If it performed perfectly for months, and sometimes perfectly now (inertmitant issue) then is it not unlikely that its just an adjustment??

It could be that deposits have formed in the idle circuit. As the choke warms up and opens the engine goes lean. Turn your idle mixture screws 1/4 turn rich (counter clockwise, if you have a digital watch you'll have to figure this out on your own). See how it runs after adjustment, this literally takes a couple seconds of work and is easily put back if it doesn't work.

All good points and a good phenolic spacer would be advisable. There are also aluminum shield plates I've had success with. Lastly, check your inlet pressure. If it's high, it may not care when cold, but could get cranky when warm.

You say it idles like crap, but how does it run/drive off idle? Have built carbs for years and it sounds like a fuel supply issue to me. Have seen it many times, especially on the Carter/Edelbrock/Weber carbs because the jets are on the bottom of the fuel bowls. You might have a piece of junk that got into the fuel bowl that is causing your problem. Something like ten screws and the center bolt and the top comes off. Take the top off and check inside the bowls, clean out all the gas and spray carb cleaner through all the orifices, pull the idle screws and do the same with the carb cleaner. Change your fuel filter, fuel with alcohol (winter blend or E85) can cause the glues in some filters to come apart and you might be passing those pieces through the carb, hence only occasional issues.

Good luck and let us know what you find.

sooo...
1. I have an alluminum spacer
2. I did try 1/4 turn richer yesterday and it DID help.. What does that mean?
3. Have not yet opened it up but sure will

oh, and it runs/drives fine when the idle is crappy..no stumble

If it runs better as you richen the idle mix and it ran fine before it means, something has made the engine run lean at idle. This could be dirt in the carb or possibly a vacuum leak, leaks can become worse as a engine warms. Even a weak fuel pump that lowers the float level. The only way to be sure about debris in the carb is to remove the top and inspect it ( you may find the bowls clean and still have a blockage in the passages, overhaul time). spraying carb cleaner around the gaskets and fittings on the intake and listening for a change in the way the engine runs can often find a intake leak. You car also richen the idle even more and see how it runs.

Opened it up.. There was a bit of crap in there.. Always a mystery how it gets in there past a filter..

Got the crap out.. Sprayed carb clnr in the jets and passages..

Idles better :) Thanks.....


When it got hot driving it today, it would not idle at all.. Im thinking thats the spacer??

Looking to order, Jegs or Summet and no listing for a Edel 1411... Are all edelbrock bases the same?

Having wrestled the immense intake manifold on a 390, I'd suspect a leak at the joint(s) to the head(s). Try a re-torque first.

4 bbl Carb bases come in two basic designs. Spread Bore, with large secondaries and smaller primaries, and Square Bore, having both primary and secondary butterflies approximately the same size.

These should work for your Edelbrock. I'll leave the choice between open center and square bore to you. Either will work with a square bore carb, but the open one will work with both types of carbs unless you have huge secondaries, like in a Holley 850. Even then, a little judicious work with a Dremel with do the trick.

http://www.summitracing.com/search/p...etor%20Spacers