Vacuum leak?

[Bob]

I was tinkering with my carb to fine tune a little bit more. The hi/lo jet adjustments on the front did not really make the engine stumble or go down when turned all the way in.
400 4bbl
Vacuum leak?

[Ghoste]

Are you talking about the mixture screws?    I'm guessing a Carter of some variety?

[Bob]

Are you talking about the mixture screws?    I'm guessing a Carter of some variety?

Yes and it's a TQ.
Bob

[Nacho-RT74]

did you seal the rear tee where the air purificator gets the vacuum to the air entry doors ?

[Bob]

did you seal the rear tee where the air purificator gets the vacuum to the air entry doors ?

All sealed up.

[Ghoste]

How is your idle quality in general, was there a problem that you were trying to dial out?

[Bob]

How is your idle quality in general, was there a problem that you were trying to dial out?

Idle was not to bad after 3 or 4 minutes. What it was doing was, no matter how cold it was it would start up, perr like a kitten for about 5 seconds and it would seem like it was loading up. I would work the accelerator a few times and it would even out when warm. It's one of those things that bothers the heck out you but when it gets a little warm it gets better. I thought about vacuum because the warmer it gets the better it gets.

[Corellian Corvette]

I use almost nothing but Carter/Edelbrock on my cars.

If your mixture screws are inefective, that means they car is somehow running on your primary circuit. Also, if they are not working SOMETHING IS WRONG.

In the Edelbrock carb, the idle screws are the only source of fuel - so if your car is getting fuel it's coming from somewhere else that it should not.

Vaccum leak would likely cause your car to die earler, since a leak leans the mixture out.

You say "load up" so my guess is you have a stuck or mis-adjusted float, causing the car to run extremely rich.

Possible issues are
High idle
Stuck Float
Sinking float
Throttle plate binding
Choke not coming off and engaing the throttle plate.

Set your idle mixture screws to a good baseline - 2 full turns out from seated.

The FIRST thing to do is to disconnect your throttle linkage and/or transmission TV so you have nothing pushing/pulling on the throttle.

Make sure that your choke is off, and look down the venturi to make sure your throttle is completely closed (primary and secondary). Use your hands to move the throttle plate and make sure it's smooth.

If your throttle is working properly, not binding, and closing completely, then you have an internal leak.

If that is working, when the car is running look down the venturi with a flashlight and see if any fuel is dripping out of the top down the bore. That's a float problem.

You can also try introducing a vacuum leak and see if the idle improves - pull hoses and see if the idle increases (if it's rich, it should get BETTER as you lean out). That will confirm rich condition.

You may want to pull the the carb lid off and post the jet/rod combination (as well as the part # of the carb) that will help tell if your carb is just super rich.

What's your vacuum reading? Also - have you looked at your plugs?

[Bob]

Corellian Corvette I will let you know the outcome.
Thanks
Bob

[Nacho-RT74]

I was thinking on the mixture screws weren't matching with seat inside base

[Bob]

Replaced base plate gasket. All good. It was the original. 
Thanks all.
Bob

[Bob]

I use almost nothing but Carter/Edelbrock on my cars.

If your mixture screws are inefective, that means they car is somehow running on your primary circuit. Also, if they are not working SOMETHING IS WRONG.

In the Edelbrock carb, the idle screws are the only source of fuel - so if your car is getting fuel it's coming from somewhere else that it should not.

Vaccum leak would likely cause your car to die earler, since a leak leans the mixture out.

You say "load up" so my guess is you have a stuck or mis-adjusted float, causing the car to run extremely rich.

Possible issues are
High idle
Stuck Float
Sinking float
Throttle plate binding
Choke not coming off and engaing the throttle plate.

Set your idle mixture screws to a good baseline - 2 full turns out from seated.

The FIRST thing to do is to disconnect your throttle linkage and/or transmission TV so you have nothing pushing/pulling on the throttle.

Make sure that your choke is off, and look down the venturi to make sure your throttle is completely closed (primary and secondary). Use your hands to move the throttle plate and make sure it's smooth.

If your throttle is working properly, not binding, and closing completely, then you have an internal leak.

If that is working, when the car is running look down the venturi with a flashlight and see if any fuel is dripping out of the top down the bore. That's a float problem.

You can also try introducing a vacuum leak and see if the idle improves - pull hoses and see if the idle increases (if it's rich, it should get BETTER as you lean out). That will confirm rich condition.

You may want to pull the the carb lid off and post the jet/rod combination (as well as the part # of the carb) that will help tell if your carb is just super rich.

What's your vacuum reading? Also - have you looked at your plugs?

After I replaced the base gasket I set it like you wrote. It was way off to begin with. Thanks for your advice. That is one for my archives.

[Corellian Corvette]

So you had a leak at the base gasket and your idle mixture adjustment was off?

Is it running better now?

[Bob]

So you had a leak at the base gasket and your idle mixture adjustment was off?

Is it running better now?

Yes, it's running much much better. I guess because of the leak I was trying to compensate through the mixture adjustments.