Okay, I've been trying to figure out the first issue I should work on with my car. In the meantime, nothing is getting done, so here I go.
I've been told by several people (most of which know very little about carburetors) that this is a carburetor problem.
When I turn my car off, it doesn't just turn off, it sputters and dies. One of many reasons I'm hesitant to blame the carburetor is because it was just replaced and the old one did the same thing. I know everyone is going to ask for details as to what I'm working with here. I'll do my best...
It is a stock, original (rebuilt) 307 V8
Edelbrock intake and I'm not sure what brand 4 barrel carburetor
The vacuums have been checked and seem to be working fine (I've been told)
I just replaced the timing chain (with a double roller) the old one had a lot of slack and may have been a tooth off but this hasn't seemed to change anything.
Everyone says my idle is really high, but if I lower it at all my car dies as soon as I put it into gear.
With the new carburetor from a cold start it will (after several minutes) usually drop to a lower (still fairly high) idle. The old carburetor never did that on its own. (I'd rev the engine to get it to drop)
Also... not sure if this is related or totally separate but is worth mentioning... from a stop if I floor the gas pedal it dies. once I get it going a little if I floor the gas it wont downshift and pick up speed, it bogs down really badly. From a higher gear if I hit the gas it doesn't seem to bog down as much but wont pick up speed either. If I slowly press the gas to the floor it seems to run as expected. (This is how I usually drive so I only just noticed it does this, not sure if it would have done the same with the old carburetor or not)

Thank you in advance for your help. If you need any more information feel free to ask. I will do my best to be as accurate as possible, if I leave out information its due to my ignorance on the topic and I apologize in advance.

 

1) Check to make sure the choke is opening fully.
2) Make sure the ignition timing is where it's supposed to be.
What rpm is the engine idling at when it's up to running temperature?

 

You don't have to apologize for anything lol, but i had the same prob with a truck i had and it was the timing. Do like Camaro69 said and make sure the ignition timing is where it's supposed to be. I just turned my distributor a bit while it was running and it fixed the prob, maybe that's whats causing the run-on?

 

I've checked the timing... is ignition timing different?
I should also add that my distributor was changed. Please correct me if this sounds wrong but I believe it is originally "points" and was changed to "electric". My uncle did it a few years ago, said it would help with a lot of problems I was having (my biggest problem was anytime someone borrowed my car they flooded the engine and I had to change the plugs) which it seems to have done.
Would that make a difference in causing these new problems?
I also have to say I spend half my time in NY and the other half in WA where my car is. So it will take a few days before I can double check these things.
I don't know what rpm it is at when idling, I'll check that as soon as I can.
As far as the choke, with the new carburetor it does eventually open (after several minutes) When I get impatient I'll rev the engine and it opens then.
As soon as I can I'll check to see how long it takes and to make sure it opens fully.
It has been suggested that I drill holes in choke to allow more air to enter. Again, this advice comes from someone who admittedly knows very little about carburetors. Do you think this could help? Currently if my idle gets any lower it dies as soon as it goes into gear, so I would be afraid drilling holes would do the same thing.

 

Okay, my boyfriend checked on my car for me
he let it run for over 5 minutes and the idle never dropped, although I know it does on occasion.
How do I check the rpms? He mentioned I don't have that gauge in my car. All I have is my speedometer, gas gauge and lights for oil pressure, temperature and generator.
Thanks again.

 

sure sounds like the timing chain is in there off a tooth. could be the mechanical advance and/or vacuum advance is not working. has anyone tried to time it by ear? first make sure the advance it working.

 

I just put a new timing chain on it about a month or so ago, mostly because we thought the same thing. The chain is on right and the timing is on as well. If "by ear" you mean just figure out where it sounds best... basically right now it sounds as good as we can get it and the timing is where its supposed to be. Unless we change the timing so it sounds like crap then adjust the carburetor.... I wouldn't even know where to begin on that.
How do I find out if the advance is working (not really sure what that means) and how do I fix it if its not?

 

lets see if i can remember this right,,,hook a timing light to it, start it up and let it idle, rev it up while looking at the timing mark, the timing should change/advance when you rev it. ive always just turned the rotor a little to make sure the mechanical advance is working. you can also hook a vacuum tester up to the distributor and take the cap off so you can see if the plate is moving. heres some of a writeup i found.

A distributor is capable of setting a timing point that is advanced by two independent methods. First, a Chevrolet V-8’s initial timing >> must be set at idle by rotating the distributor clockwise for retard or counter-clockwise to advance. This initial timing point acts as a base point for the engine’s ignition system. Once initial timing is set, there are two ways of adding additional timing to an engine. One method uses a vacuum canister designed to work off a ported vacuum source (Holley carburetors locate this on the metering block), which is typically referenced from just above the closed throttle blades. As the throttle begins to open, the engine displays its highest level of vacuum and causes the distributor’s vacuum canister to advance the timing.

Mechanical advance is the second method of ignition timing advance. As the distributor spins fast enough to activate the mechanical-advance weights, the engine receives initial timing, mechanical timing, and vacuum timing under part-throttle conditions. As the engine accelerates to wide-open throttle (WOT), the vacuum drops, eliminating the vacuum canister’s timing. For example, part-throttle total timing would look something like this: 10 degrees initial + 10 degrees vacuum + 20 degrees mechanical = 40 degrees of total timing. At WOT, there is no vacuum present and the canister timing is eliminated, giving your engine a total of 30 degrees timing. The reason your engine is able to sustain more timing at part-throttle is because only a limited amount of air and fuel make it into the cylinder at part-throttle. Lower cylinder pressures enable the combustion process to start sooner and help improve part-throttle response by increasing torque. This additional part-throttle timing improves efficiency and torque.

 

so we got under the hood again yesterday. The initial timing is set correctly, when we rev the engine the timing does advance. We checked the vacuum on the carb, is there supposed to be vacumm pressure at an idle, or does that only open up when you begin to rev the engine? My car has seems to be recieving vacuum while idling but the vacuum pressure doesn't seem to change when the engine is revved.

 

vacuum should drop at throttle up. when the butterflies open it lets air in and you lose some vacuum. could be that the carb needs cleaning. if you do that its a good idea to change plugs afterwards.