Holley carb. gurus needed!

[82 GT]

My car is running pig rich at idle ever since I swapped the 69/78 jets for 72/80 jets. I have to keep my foot on the gas at stops or it will stall out on me. Once I'm up and running, it seems ok. It fouled out the plugs I had so I bought a brand new set, drove it for a mile and now they're black!
I'm noticed raw fuel dripping from one secondary ventri when it's idling. I don't think that's supposed to happen...is it?
What would cause this? Is there anything I could have done when swapping jets? I fail to beleive that 72/80 jets are too much jet for my setup.
Why is raw fuel dripping into the secondaries at idle and still drips after the car is shut off?

[Dark Knight]

Needle valve probably has some dirt in it holding it open. Probably need to pull it out and check it. And it is kind of a big jetting.

[6T9PONY]

I don't know the answer to your question, but PKRWUD knows his Holleys. He built a 3310 for my fastback that is amazing! I'd try to get ahold of him somehow.

[Jeff Chambers]

Fuel should not be dripping from the boosters. Either a float is stuck or the float level set too high. Also, does your carb have four corner idle adjustment? If so, set the idle screws for maximum vacuum at your desired curb idle setting.

[~The Jester~]

Exactly! Floats are too high, or needle/seat is stuck open. You did kick up the fuel pressure too, but I seriously doubt that 6.5 PSI will blow past the needle valve, but if they're getting weak/old that could be your problem too.

Check float level first!

[82 GT]

The problem seems to be fixed now. All I did was remove the secondary bowl again, checked for any debris and put it back on again. I don't know what was wrong....
I DID notice that the two front idle screws screws want to be turned ALL the way IN or it won't idle right. What does that mean?
FWIW, I only have two corner idle adjustment.
Other than that, it seems to run fine now but I don't think the idle screws should be all the way in like that......

[Jeff Chambers]

Nope, you shouldn't be all the way in with them. That says to me that its getting fuel elsewhere other than the idle circuit. Might try replacing the metering block gaskets.

[Jeff Chambers]

Nope, you shouldn't be all the way in with them. That says to me that its getting fuel elsewhere other than the idle circuit. Might try replacing the metering block gaskets.

[82 GT]

Somone suggested something about cracking the secondary butterflies open until about .030 of the trasfer slot is exposed. I don't know what that all means or how to go about doing it.......

[Rev]

Sounds like to me that the secondary fuel inlet valve (needle and seat) had some trash in it causing an over fill of the secondary float bowl with concommitant dipping out of the boosters. I've had that happen on Holleys and just replaced the needle and seat. Anyway, that sounds like it is fixed now.

I had to drill the low speed air bleeds a little larger on my Road Demon. That changed the Idle ajustment (would only idle at about 1/8 turn out) to a more reasonable 1 1/2 - 2 turns out from closed position. That also allowed a better low speed engine part throttle when running off of the transition slots before the main jets kicked in.

You really ought to get a good Holley book to learn the "ins and outs" of tuning the Holley for best performance.

Rev

[82 GT]

Originally Posted by Rev

You really ought to get a good Holley book to learn the "ins and outs" of tuning the Holley for best performance.

Rev

Actually, I do have a book called SUPER TUNING AND MODIFYING HOLLEY CARBURETORS.....I'm just too lazy to read it....LOL

[Dark Knight]

Might check the primary side for dirt/high float level too. How high do you have the idle set? You can also crack open the secondaries a little more, there's a screw underneath.

[82 GT]

My idle speed is around 1000rpms. I was wondering if an idle speed that high negates the idle mixture adjustments.
I checked the floats and they are set so that fuel just trickles out the sight plugs.
It runs fine now since I took the secondary bowl off again and blew out any debris that might have been in there and replaced the gasket.
It's just that the idle mixture screws don't work now. It wants the screws all the way in.
I didn't check the transfer slot on the butterflies to see how much is exposed yet. I don't really want to remove the carb. and mess around with that unless I really need to.
Since I don't know much about carbs, I'm always afraid I'm going to screw something up and make it much worse that what it was.

[Dark Knight]

Does it have to idle that high? Setting the idle speed in gear?

[82 GT]

1000rpm idle speed is normal with a performance engine...isn't it?
Why would I want to set my idle speed in gear? That would give me an even higher idle in park.

[lx mike]

Originally Posted by 82 GT

1000rpm idle speed is normal with a performance engine...isn't it?
Why would I want to set my idle speed in gear? That would give me an even higher idle in park.

That might be why the idle mixture screws aren't doing anything.


where does the idle drop when you put car in gear?? 1000 is kinda high unless you need it there to keep from stalling.


last but not least: GO READ THE BOOK!!!

[82 GT]

This isn't exactly a stock cam I'm running here. It's not like it' s going to be content idling at 700-800rpms. I've tried lower idle settings...it's doesn't like it. It's not because the engine will stall but it's just one of things you just KNOW by the sound of the engine. You gotta give an engine what it wants.

[Dark Knight]

Have you tried lower idle settings and then adjusting the idle mixture? Thats NOT a big cam.. with a LSA of 110* it should idle decent... might double check the rocker adjustment.

With an auto, you adjust the idle speed and mixture in gear... unless you put in neutral or park at a light...

[82 GT]

Yep, I tried lowering the idle and adjusting the mixture........didn't work.
I probably have to adjust the butterflies to expose more of the transfer slot on the secondaries but as long as it idles fine the way it is , do I really need to mess with the transfer slot? I'm trying to avoid taking the carb off, flipping it upsidedown and all the stuff unless there're a performance gain to be had.......
No, it's not a huge cam but the XE series cams have more aggressive ramp rates compared to the comparable cams of the Magnum series.
The numbers make them look small but the engine is made to think it's bigger than it actually is......but that's for another discussion.

[Rev]

I use a CC 268EXE (224/230@ .050) which replaced a CC 268HE (218/218 @ .050). That's a little milder than your's but not too much. At the same time that I changed the cam, I went from an Edelbrock Performer to a Performer RPM Air Gap intake manifold.

To make a long story short, I ended up almost completely recalibrating the carb (Road Demon 625) to make things work correctly. I had to rejet the mains larger, add a 50cc. accelerator pump, change the accelerator pump squirters (smaller or larger, I can't remember), go to a lower # power valve (4.5 in.HG), enlarge the power valve restrictor channels, and finally enlarge the low speed air bleeds.

All this took a couple of months of experimenting. I couldn't have done it without reading and rereading my Holley book several times. The car now "barn storms" from off idle to 6000 rpm red line with nary a hiccup. At times, I wondered if I would ever get it right, but I finally did.

The tech dept. at Barry Grant was no help at all. They just told me I had the wrong carb and to buy the correct new one. When I asked them about altering the one I had, they just said I was going to ruin it and to leave the calibrating to them. I'm now glad that I didn't listen to them (saved me several hundred bucks).

Well that's how it went for me, good luck with yours.

And lest I forget, I had to go from a TCI 2500 stall convertor to a TCI 3000 stall convertor to match up with my new power band.

Rev