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Rebuilding the Quadrajet

alright...I put the screws close in as per instructions in the manual...so I think it should be okay.
I put it on today. And fired it up at 8:00...I had to go so I turned it on for a few seconds then off. Few questions...

When I fired it up the second time, I let it "idle" a bit. But either it is cold from sitting for so long, or the choke is sticking because it was staying at around 1300 RPM. I'll see how it is tomorrow. I have a leak I need to fix.
There are 2 hoses coming from a black "can" by the core support. On goes on the base of the q-jet, and one goes slightly above and to the right. The one on the top had a little crimp to hold it on. But the bottom one I can't remember if it did or not. It didn't have a crimp on the hose when I went to put it on. So I just put it on without one.
But when I start it up it leaks bad from that spot. I'm guessing I need a crimp there? (Crimp= hose clamp that you use pliers to squeeze to take pressure off, I don't know the name)
Also, what do I have to go with timing and idle mix when I go to work on it tomorrow? I don't know anything about timing.
thanks
 
Have fun rebuilding yours! I just got the Holley 770 Truck Avenger carb... that thing is baaaaaaaaaaaaaaaaaaaad! :saweet:
 
Steve, Might try the best Kept secret for Quadrajets...National Carburetor,Inc in Jacksonville, FL. Ask to speak to Eddie in Tech. You'll be glad you did. His work is AWESOME and the price can't be beat. He rebuilt mine and it is... AWESOME!
 
Dorian, The leak I thought I had accured around the 2 vaccum lines (im pretty sure thats what they are, 2 black hoses because the fuel line on front of carb. One hose goes underneath the fuel filter, and curves beside the thermostat housing.
But the leak wasn't that, it was fuel. I found it though. i forgot to tighten the fuel filter nut after I rebuilt the carb. So no more leaks.

I ran it today, drove it for a couple minutes. Have 1 problem...
The idle is too high. It idles around 1200-1800 RPM. And I am not sure if the choke is working or not...i'll worry about that after I adjust the idle though.

I will read through the manual and see if I can find out.
Until then, anyone want to give me advice on how to lower the idle?
Also...

WOOHOO I REBUILT SOMETHING AND IT WORKED!
A big thanks goes to James (jiminycricket) for sending me the manual. And everyone who replied/responded/helped me out in the process. I have a smile from ear-to-ear :laugh:
 
Check your idle speed stop/screw adjustment, you may have to back it off. Also make sure your choke is working properly and not hanging up on the fast idle cam.
 
I went out there and tried adjusting it. I failed.

I don't have the proper tool, so I was just tiny needle-nosed pliers.

I screwed them in, to make the idle lower, right? I turned them in, and either the choke is catching on something, or something is wrong with what I am doing.
before it was around 16-1800 RPM yesterday in neutral. Now it's at 2000 RPM. BUT before that it idled around 1100-1300 after i screwed the needles in a bit.

Any advice?
 
went out to start it again. It wouldn't start. Took me 5 or 6 tries and a total of 16 minutes to start. I don't know why that happened.

Then it started after i floored the gas pedal... :confused:
Anyways it idles at around 1400-1600 RPm now instead of 2000. This is really confusing me :confused:

Also, the stock fan blows a lot of air :blush:
 
Choke is likely going to be part of the issue. Is the choke blade fully open when the engine is warm? If you can force it open further while the engine is running, (and warm) then you need to adjust the choke. Blade needs to be vertical on a hot engine.

Flooring the pedal is the "clear flood" mode for these carbs, so it may have been flooded. One to two pumps on a cold engine is all that should be required to prime the engine and shut the choke.

The little screws are not used for setting minimum idle speed, the one on the drivers side is. The two in the bottom are the idle mix screws, use those once you get the carb closer to working right. Idle needs to come down first.
 
Thanks dorian. I will take some pictures of the carb when the engine is running. I'm so lost when it comes to the choke still. don't really understand, need to review the manual again.

DOH i got mixed up with the screws. I will go try adjusting the RIGHT (correct) one!
 
Alright...
looked throough the manual.
for clarification of what I remember
the 2 screws with weird heads are idle mixture.
the screw on the right is the throttle stop screw
the screw on the left by the choke is fast idle screw

I played around with the fast idle screw...screwed it in two 1/3-1/2 turns and it went up to 1800 RPM. Backed it out 1 full turn, maybe more. Now its around -/+ 800 RPM on idle

Does this sound okay? The sticker on the core support says 700 or 800
 
Fast idle is for choked operation...how fast the engine runs when its cold.

You want to mess with the throttle stop for "curb idle".
 
so should I screw that fast idle back in 1 full turn, to try to get it close to what it was before I messed with it? :crazy:
 
also, when you say "cold" does that mean when it hasn't been ran for a few hours/overnight. or when the actual climate temperature is cold? Just a stupid clarification :o

What should the engine run at when its cold? So i can mess with it tomorrow to get it back to normal.
 
I set my fast idle speed extremely low, like 1000RPM or something. That's because it's a manual transmission and it didn't need much choke even with icy cold. Been a couple of years since the carb though. Auto trans will need to be higher if you don't wait for the fast idle to come off before putting it in gear.

Should be a sticker on core support for "factory" fast idle. It's the emissions sticker.

If you've messed with it, you probably want to set it back close to what it was, and start again from there.

Cold I mean first thing in the morning. Electric chokes are a bit out of my realm of expertise. I know they use a bi-metallic coil, however they also self heat, so the choke will go fully open from around 3 minutes to 10 minutes, (approximately, my dad was testing various) they vary. That is of course, if the engine is running since the oil pressure switch cuts power to the choke with no oil pressure.

Since it's still a bi-metallic coil, any latent heat from previous starts keeps the choke open more than if the engine were completely cold, regardless of the electronics in the choke. It takes a LONG time for an engine to get back to ambient air temperature, and if you screw with the choke while the engine is even close to warm, your results are going to become skewed based on outside air temp. Once it cools off, you'll likely have problems.

This is why I don't recommend messing with the choke unless it's absolutely necessary.
 
Does the fast idle effect the choke? Or is the choke messing up too?

When is the best time to put the fast idle close to where it was before, and then adjust the throttle stop? Tomorrow? or does it matter?

Also, after I get the idle figured out, how do I figure out the idle mixture?
 
OK, fast idle you set with the engine cold, right after you start it in the morning. IF the choke is working right, then you've set your fast idle. Once your choke "kicks down" you aren't using fast idle.

Fast idle is a function of the choke. It's all tied together through the linkage "behind" the choke. If choke doesn't fully close, I don't believe you will get to fast idle.

Once the engine is warm, again assuming choke is working right and fully open, you can set the idle speed.

A few ways to figure out idle mix, one is to adjust them while hooked up to a vacuum gauge, highest engine vacuum possible is what you strive for. Never tried that method, probably the best.

Other way (which I use) is set them both at 2.5 or so, and then screw in one until idle quality starts to decline, then back it off until its better, then the other screw, and so on back and forth until you get them right.
 
Alright dorian thanks. That cleared up a lot of confusion. sorry to keep hassleing you :doh:
I will play around with the idle mixture tomorrow. After I get my fast idle, and curb idle figured out.
If I have the idle mixture off a bit, will it harm anything? I just don't have any experience with tuning engines, so what may sound good to me, may only be satisfactory for someone who is experienced.

Thanks
 
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