Still stalling after carb rebuild. ???

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Troub

Troub

67 Dart 270, 225 slant six
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so the rebuild on the Holley 1920 is complete, put it back on the Dart, she fired right up and sounded waaaaay better than before the rebuild but although she sounded smooth and ran without stalling for twice as long as before the rebuild......she still stalled. Same issue as before, once stalled she won’t fire up without you’re foot on the glass and once you release the pedal she immediately stalls. Takes a long while before she will fire up again with pressure to the pedal. Playing with the idle adjustment screw doesn’t seem to make much of a diff although I’m a novice and this was my first rebuild. Pics posted......I question the linkage on the float bowl vent as the other end of that rod just hangs there and I don’t see how it does anything without being connected. That is how it was when I removed the carb I originally. Thoughts on any or all of this?

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Troub said:
so the rebuild on the Holley 1920 is complete, put it back on the Dart, she fired right up and sounded waaaaay better than before the rebuild but although she sounded smooth and ran without stalling for twice as long as before the rebuild......she still stalled. Same issue as before, once stalled she won’t fire up without you’re foot on the glass and once you release the pedal she immediately stalls. Takes a long while before she will fire up again with pressure to the pedal. Playing with the idle adjustment screw doesn’t seem to make much of a diff although I’m a novice and this was my first rebuild. Pics posted......I question the linkage on the float bowl vent as the other end of that rod just hangs there and I don’t see how it does anything without being connected. That is how it was when I removed the carb I originally. Thoughts on any or all of this?

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So she was stalling before the rebuild? Are you sure you have a fuel problem, done all the default troubleshooting? Good fuel pressure? Consistent spark? The running cycle getting progressively shorter as the car warms up? All stock? Set the idle screws at 1 to 1-1/2 and leave. Check the static timing(TDC)
 
Nice pictures of the bowl vent and linkage but how about the rest of the carb. What is the idle speed set at? Never overlook the obvious or the basics.
 
Troub said:
so the rebuild on the Holley 1920 is complete, put it back on the Dart, she fired right up and sounded waaaaay better than before the rebuild but although she sounded smooth and ran without stalling for twice as long as before the rebuild......she still stalled. Same issue as before, once stalled she won’t fire up without you’re foot on the glass and once you release the pedal she immediately stalls. Takes a long while before she will fire up again with pressure to the pedal. Playing with the idle adjustment screw doesn’t seem to make much of a diff although I’m a novice and this was my first rebuild. Pics posted......I question the linkage on the float bowl vent as the other end of that rod just hangs there and I don’t see how it does anything without being connected. That is how it was when I removed the carb I originally. Thoughts on any or all of this?

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First pic in the previous post shows the free end of the bowl went rod just hanging there at bottom right......posting more pics of the carb in case I am missing something else in the linkage that you guys can spot. I gotta solve this stalling prob!

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Does the idle mixture change the way the engine runs?
Seems like choke cones off abd it starves for fuel.
That or you have a fuel delivery problem.
After stall,key off does accellerator pump squirt gas when you activate throttle ?
 
What have you done to the rest of the fuel system? Tank, lines and such?
 
toolmanmike said:
Nice pictures of the bowl vent and linkage but how about the rest of the carb. What is the idle speed set at? Never overlook the obvious or the basics.
Click to expand...
Rest of carb pics now up mike. Idle speed screw was screwed all the way in. Again, I’m a novice at carbs, the rebuild went well
69FBCuda said:
So she was stalling before the rebuild? Are you sure you have a fuel problem, done all the default troubleshooting? Good fuel pressure? Consistent spark? The running cycle getting progressively shorter as the car warms up? All stock? Set the idle screws at 1 to 1-1/2 and leave. Check the static timing(TDC)
Click to expand...
yes, she was stalling before the rebuild after About 3-5 min and sounding rough, after rebuild she sounds much smoother and idles for about 6-8 before stalling. New fuel tank, lines, filter, the filter stays full, I have all three idle screws in same setting they were when I got the car. Pics of them here....idle vent screw (correct me if I’m calling it incorrectly) is all the way in. I did adjust the float to spec when I did rebuild.

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Just after the engine stalls, leave it off and look into the carb and operate the throttle to see if any fuel is squirted properly.

- If not, the float could be set too low.
- The fuel tank is drawing a vacuum because of blocked vent(s) or lack of vented fuel cap (remove fuel cap after stalling and check for hissing/air rushing in.
- Fuel too old.
- Wrong ignition timing.

There's an idle Mixture screw, and an idle Speed screw.
During tuning, the Speed screw needs to be adjusted so the engine keep running at its designed rpm.
 
Troub said:
so the rebuild on the Holley 1920 is complete, put it back on the Dart, she fired right up and sounded waaaaay better than before the rebuild but although she sounded smooth and ran without stalling for twice as long as before the rebuild......she still stalled. Same issue as before, once stalled she won’t fire up without you’re foot on the glass and once you release the pedal she immediately stalls. Takes a long while before she will fire up again with pressure to the pedal. Playing with the idle adjustment screw doesn’t seem to make much of a diff although I’m a novice and this was my first rebuild. Pics posted......I question the linkage on the float bowl vent as the other end of that rod just hangs there and I don’t see how it does anything without being connected. That is how it was when I removed the carb I originally. Thoughts on any or all of this?

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Default for the idle mix screw is 2 turns out up until 1969 then it is vacuum set to 14.2 to 1. Check the float level via the economizer diaphragm opening, should be 27/32th from the machined surface to the gas surface. Is the bowl vent operating lever missing?
 
The two spring loaded screws that are side by side in the pics are your curb idle (closest to the carb) and your fast idle ( only functional when the choke is on). The spring loaded screw at the base of the carb is your idle mixture screw and should not be all the way in.
Probably more like 1 1/2 to 2 turns out from lightly seated. Ig you've had this all the way in the whole time, Then I'm sure that it would not stay running.
 
Troub said:
Rest of carb pics now up mike. Idle speed screw was screwed all the way in. Again, I’m a novice at carbs, the rebuild went well

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This could very well be your problem. All in is not correct, you are not getting ANY fuel at idle, set the idle air mixture screw to 2 turns out to get it running, then put a vacuum gauge on the intake port.
 
Tooljunkie said:
Does the idle mixture change the way the engine runs?
Seems like choke cones off abd it starves for fuel.
That or you have a fuel delivery problem.
After stall,key off does accellerator pump squirt gas when you activate throttle ?
Click to expand...
I played with the idle mixture screw while running and it had no discernible effect on the way she was running.
 
69FBCuda said:
Default for the idle mix screw is 2 turns out up until 1969 then it is vacuum set to 14.2 to 1. Check the float level via the economizer diaphragm opening, should be 27/32th from the machined surface to the gas surface. Is the bowl vent operating lever missing?
Click to expand...
Right now the idle mix is all the way right. I will turn out 2 as you suggest. I adjusted the float when rebuilding to the 3/16 the Mikes Carb kit stated. The bowl vent lever just hangs there by the idle screw and is not attached to anything. Is this correct?

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69FBCuda said:
So she was stalling before the rebuild? Are you sure you have a fuel problem, done all the default troubleshooting? Good fuel pressure? Consistent spark? The running cycle getting progressively shorter as the car warms up? All stock? Set the idle screws at 1 to 1-1/2 and 1-leave. Check the static timing(TDC)
Click to expand...
Back off to 1-1/2 on all three from tightest point? Yes, as she warms up at one point you hear hear the engine start to slow and about 15 sec later she stalls.
 
Troub said:
Back off to 1-1/2 on all three from tightest point?
Click to expand...

Do not seat the air/fuel screws too tightly, but yes, gently seat them and back out 1 1/2 turns.

Keep in mind that is just a starting point. Once you can keep it running, then adjust them with a vacuum gauge to max vac reading on the dial then back it in just a smidge..
 
Troub said:
Back off to 1-1/2 on all three from tightest point? Yes, as she warms up at one point you hear hear the engine start to slow and about 15 sec later she stalls.
Click to expand...

There should be only 1 idle air mixture screw. Just below the fuel line fitting.
 
Dana said:
The two spring loaded screws that are side by side in the pics are your curb idle (closest to the carb) and your fast idle ( only functional when the choke is on). The spring loaded screw at the base of the carb is your idle mixture screw and should not be all the way in.
Probably more like 1 1/2 to 2 turns out from lightly seated. Ig you've had this all the way in the whole time, Then I'm sure that it would not stay running.
Click to expand...
I have now moved the idle mixture screw out 1-1/2 as suggested. With car cold and choke closed where should fast idle be adjusted too?
 
Troub said:
Back off to 1-1/2 on all three from tightest point? Yes, as she warms up at one point you hear hear the engine start to slow and about 15 sec later she stalls.
Click to expand...

The other 2 screws are external and adjust the levers. Curb idle(for setting the RPM after you get it running ) and fast idle(choke)
 
Troub said:
I have now moved the idle mixture screw out 1-1/2 as suggested. With car cold and choke closed where should fast idle be adjusted too?
Click to expand...
The fast idle screw will bet set in further than the curb idle screw. You have to play with the fast idle while the choke is closed and cold(enough to keep the cold engine running but not crazy high ~1000-1200 rpm) Someone else my know better on this.
 
Troub said:
Back off to 1-1/2 on all three from tightest point? Yes, as she warms up at one point you hear hear the engine start to slow and about 15 sec later she stalls.
Click to expand...

You shouldnt really need the choke in 50-60 degree weather, my 4160 love this temp
 
69FBCuda said:
The fast idle screw will bet set in further than the curb idle screw. You have to play with the fast idle while the choke is closed and cold(enough to keep the cold engine running but not crazy high ~1000-1200 rpm) Someone else my know better on this.
Click to expand...
With the choke closed I would set the screw to the next to highest notch on the cam. I see you are in FLA. so you really don't need a high fast idle.
 
Troub said:
I played with the idle mixture screw while running and it had no discernible effect on the way she was running.
Click to expand...
Then carb needs to come apart again, the ports werent properly cleaned. The idle circuit is blocked. There are tiny ports and tubes with pinholes in them,that need to be cleaned. Most times i use a strand from a wire brush to open them up. Test for flow with carb cleaner, blow out with compressed air.
 
Troub said:
I played with the idle mixture screw while running and it had no discernible effect on the way she was running.
Click to expand...

With the idle mix seated all the way it will likely die out, same if it's out too far.

T J is correct, if there is zero difference when turning it in or out it is probably clogged passages.

Is the end of the curb idle screw making contact at all.

If it isn't, turn it in until it does and give it another 1/4 turn, start it and see if it stays running.

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