Still stalling after carb rebuild. ???

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So hard to sort through because if he had the curb idle screw all the way in, then he wasn't on the idle circuit at all, which would be why the idle mixture screw had no effect.
 
Bad Sport said:
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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I agree, if screw isnt adjusted to slightly open butterfly valve then the idle mixture wont change anything. Same if its open too far.
 
The carb kit comes with instruction/spec sheet, usually there is a baseline for throttle plate and choke adjustments.
 
If it's a solid lifter engine, the very first thing I would do is reset the valves; I use .013intake/.023 exhaust at about 60* ambient temp. Make sure the feelers you use are a little narrower than the valve stems, so they fit exactly right and don't bridge over worn rocker arms.
 
Troub said:
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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From what I can find it doesn't attach to anything

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Almost sounds like something electrical is heating up and failing. Have you checked that it's still getting fire when it quits?
 
AJ/FormS said:
If it's a solid lifter engine, the very first thing I would do is reset the valves; I use .013intake/.023 exhaust at about 60* ambient temp. Make sure the feelers you use are a little narrower than the valve stems, so they fit exactly right and don't bridge over worn rocker arms.
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Let's not go there AJ.
 
RustyRatRod said:
Almost sounds like something electrical is heating up and failing. Have you checked that it's still getting fire when it quits?
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True that. When it stalls you have to do some diagnosis. Does it have spark/ Does it have fuel/ Does it have compression? Spark and fuel can go away. rarely does compression go away unless AJ has been under the hood adjusting valves. :poke::poke::rofl:
 
Tooljunkie said:
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.
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I did that, cleaned and blew out then made sure I could see light through.
 
toolmanmike said:
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.
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Do this before starring mike?
 
69FBCuda said:
From what I can find it doesn't attach to anything

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Yeah I don’t get that lever. If it just hangs there then how does it function as there is nothing acting on it. Why does it have a spring in the middle of the rod? Should it just always be closed down on the bowl vent port then?
 
Troub said:
Yeah I don’t get that lever. If it just hangs there then how does it function as there is nothing acting on it. Why does it have a spring in the middle of the rod? Should it just always be closed down on the bowl vent port then?
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Have you checked or replaced the points and condenser, another thing to look at is the ballast resistor. Any backfiring or rough running?
 
Troub said:
Yeah I don’t get that lever. If it just hangs there then how does it function as there is nothing acting on it. Why does it have a spring in the middle of the rod? Should it just always be closed down on the bowl vent port then?
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Wouldn't keep it from running unless it clamps down and doesn't let fuel into the bowl. Its just a vent.
 
The bottom of the bown vent rod is activated buy the large flat washer on the curb idle screw. At idle the washer will hold pressure on the end of the rod holding the vent just barely open, when you open the throttle the washer moves away from the rod letting the vent close on the bowl.
Idle circuit in carb is plugged and throttle plates are to far open for vent to operate and motor is not staying running do to plugged idle circuit.
 
69FBCuda said:
Have you checked or replaced the points and condenser, another thing to look at is the ballast resistor. Any backfiring or rough running?
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Have not checked points or condenser. No backfiring and running fairly smooth.
 
toolmanmike said:
Yes
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Update: set the curb idle screw then gave it a 1/4 turn, started her up, ran fine for about 5 min then started to slow so I turned the curb idle about 1/2 turn, pepped back up, started to slow again so gave it another half turn, pepped up then slowed again, another turn and then she stayed running, turned her off after 10 min total run time from initial crank. Any thoughts?
 
lkopaska said:
The bottom of the bown vent rod is activated buy the large flat washer on the curb idle screw. At idle the washer will hold pressure on the end of the rod holding the vent just barely open, when you open the throttle the washer moves away from the rod letting the vent close on the bowl.
Idle circuit in carb is plugged and throttle plates are to far open for vent to operate and motor is not staying running do to plugged idle circuit.
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Thanks for explaining the vent bowl rod. I may take carb apart again to double check all passages got cleared. I know for a fact the idle mixture port is 100% but the idle vent port may need another check. I’m curious as to why it would run fine for a bit or at all if the idle circuit was gummed up? Again, I’m a learning novice here.
 
You have the throttle plates opened up to transition point so I just pulls just enough fuel to run. The idle circuit opening is a small hole inside the Venturi of the carb below the plates when closed,
This is what is plugged, it can't get fuel to run on with idle adjustment screw backed out to spec. That is why the mixure screw has no effect on adjustment.
 
lkopaska said:
You have the throttle plates opened up to transition point so I just pulls just enough fuel to run. The idle circuit opening is a small hole inside the Venturi of the carb below the plates when closed,
This is what is plugged, it can't get fuel to run on with idle adjustment screw backed out to spec. That is why the mixure screw has no effect on adjustment.
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This is the hole that you will see the tip of the idle mixture screw at its opening if the screw is fully seated correct? Right below the throttle plates, Or are you referring to another port?
 
That is the correct Port but fuel is not getting to that circuit for some reason, with mixture screw set throttle plates sould be just barely open at idle, and mixture screw should very idle speed from lean to rich.
 
lkopaska said:
That is the correct Port but fuel is not getting to that circuit for some reason, with mixture screw set throttle plates sould be just barely open at idle, and mixture screw should very idle speed from lean to rich.
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I did just see a you tube from Mikes Carbs on the “Holley 1920 Idle Circuit” where he mentions an idle vent port in the main barrel? He tries to show it but doesn’t, he says it’s a brass colored port??
 
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