Chris9450

Just bought a brand new Holley 4165 Double Pumper(List #6210) w/mechanical secondaries and vacuum choke. It's the direct replacement for the quadrajet. Anyway, the engine ran fine with the original carb, but ever since I've put this new one on it won't idle at less than 1500 rpm, and runs crappy at that...I'm running ~4.5-5 psi fuel. We've checked and rechecked the needles and floats and they are all fine. Just can't get the car to run. I've checked all of the vacuum lines so I'm pretty sure there's not a vacuum leak. Any ideas? I try to tune it and it's almost like the tuning screws do no good, the engine runs the same with the screws 4 turns out or completely seated...I dunno what's going on with this thing...

Stephen 87 IROC

First thing I'd say is that you have a vaccum leak somewhere especially since you say it has a high idle. Don't forget the large vaccum port at the rear of the carb for the power brakes.

Chris9450

had a small vacuum leak that was fixed, now the engine idles fine for about 5 minutes and then starts running really cruddy and won't stay running when I put it in gear...any ideas?

Stekman

What's the idle speed in park and in drive? Or, when in drive, just before it dies.

Chris9450

Here's was happens...Car idles around 1300-1500 out of gear(I know its high..but I'm taking what I can get at the moment) and around 750-900 in gear meanwhile sustaining a stable 15-20 inHG vacuum. It will run like this for about 10 minutes and then the idle becomes very rough..bouncing up and down(1k-2k) and runs extremely ragged in drive(~400-500) for a few seconds and then just dies. I plugged all the vacuums on the carburetor and ran one line from the manifold to my vacuum gauge while doing this. I had to crack the secondaries a bit with the adjustment screw to get it to idle at a reasonably stable rpm...I don't know what else to do. I'm online right now if anyone is on and would like to help me about this my aol im name is GCPlayah2083.

Stekman

I still say you have a vacuum leak. What vacuum items do you have hooked up?

And what happens if you press the gas a bit while its going to die? Does it not die, or at least, not as fast?

Chris9450

on the large front manifold vacuum I have the power brakes hooked up to..I'm pretty sure that's not leaking because I took the hose off and blew into it and it didn't leak at all. All the other vacuums are plugged on the carb, and the manifold vacuum is going straight to the vacuum gauge. When it's about to die if you tap the gas the rpm will straighten up and stay at about 1500 for a few seconds and then it'll try to die again, but the longer the engine is running the worse is gets. I've heard that you can spray wd40 on the carb gasket, intake gasket, etc and that that's a quick way to find out if you have a leak or not, maybe I should do that?

Stekman

Some aresol item. I use carb cleaner. Listen for a jump in the RPM. If it jumps, you've found the leak.

Chris9450

I'm going to give that a try tomorrow, I have some carb cleaner I can use. Are there any other reasons it might run ok for 10 minutes and then start running really cruddy?

angel71rs

Do you get any effect from the idle feed screws now? If not, you are still rich. The fuel level is ok when you pull the sight plugs?

Other cause could be a popped power valve or casting porosity. Also if the idle stop screw is set too high, the intemediate feed slots will start kicking in extra fuel.

Is the choke mechanism kicking out all the way? Also some qjet intakes have an exaust passage right at the carb pad. Takes a special base gasket. If you use a regular base gasket, will burn it and cause massive unintentional EGR. I fixed that on a car once by plugging the 2 holes at the carb pad with wooden dowels.

Chris9450

The 4165 didn't come with sight plugs. I have no idea why Holley didn't put them on. I've adjusted the secondary butterflies so they open a little. The tuning screws do a little to how the engine runs but still doesn't work very well. The car flat out won't idle if the rpm are lower than 1500 out of gear. I can take some pictures of the carb if that would make it easier. Since I adjusted the secondaries to open a little bit on idle it does idle better, but still won't idle at less than 1500. As far as the choke linkage I'm not quite sure what it's suppose to look like, but the vacuum diaphram does pull it closed when the car is running...I'm running out of ideas, it's almost tempting to fix the old leaky quadrajet and put it back on the car.

angel71rs

Do you mean it closes as in chokes the engine? Does it come off after the engine is warmed up? What does it use to pull the choke off after it warms up, a bi-metal coil mounted on the manifold or is it electric?

Chris9450

when the engine is running the diaphram pulls the choke flap on top closed a little, but that's it, I think when the vacuum drops it opens it more but other than that I don't know what it does. I've been tinkering with the carburetor and it idles a little better, now holds a steady 15 inHg vacuum, but the rpm randomly jumps up a little while the car is idling. Not really sure what's causing this. I've sprayed carb cleaner on my intake and carb to check for leaks and nothing happened, no jump in the idle or anything. As far as the choke linkage it closes slightly when there's a vacuum but it opens when the vacuum drops...not sure if this is exactly what you'd call a "choke" but it's the only thing I have that closely resembles one.

there's a picture of the top of it...I can take one of the side if that would make it easier. If there's any other imformation you need lemme know...I'm still running out of ideas.

angel71rs

The pic you posted is of a carb meant to work with a bimetal choke coil that would sit on the exaust crossover of the intake. When cold, the coil tighens. A rod hooks the end of the coil to the choke linkage of the carb. The cold coil closes the choke blade to richen the fuel mixture on cold days. The choke linkage also has a fast idle cam to kick up the rpm's so the engine doesn't die on cold starts. There is a fast idle stop on the passenger side of the carb.

Once engine starts, vacuum is fed to the choke unloader diaphram to open up the choke blade a little so engine doesn't get overwhelmed by excess fuel. Once choke coil is hot, it extends and forces the choke blade completely open.

On warm/hot days, the choke plate should be straight open. If the linkage isn't hooked to a bimetal coil, it is basically fee floating and could engage the choke linkage. Might mean the fast idle stop is controlling engine idle speed, not the throttle idle speed screw. Could also mean the blade might close enough to choke carb and introduce extra fuel. Without seeing how much the blade is coming over, couldn't tell you.

I usually just lock out the choke mechanism with a small rod on Holleys. But that is on 3310's and double pumpers that use a manual cable setup to control the choke. Your carb is meant to use a coil like the qjet did.

Is the coil still on there and hooked up? If not, you are going to have to install a coil or manually defeat it. In west Texas, a choke is not strictly needed, don't know about where you live.

If the choke coil is on there, make sure it is not broken. The center rod can break loose on it's mount and randomly cause the choke to engage.

Chris9450

Ah that would make sense. The guy I bought the carb from didn't tell me that I would need to keep my original choke around. As far as the weather where I live...it's 80 on a cool day (while I'm writing this at 1:00 AM EST it's 87 outside) so I doubted I would need the choke right now anyway. We managed to tune the secondaries better today and got the idle down to about 1100 in gear 700 in gear. Thanks for the help