I need to purchase an electric choke conversion for my Holley 4 barrel carb. List 80457-13. I believe it’s a CFM 600. Having trouble figuring out if it’s internal or external. The only vacuum hose that comes off the carb goes to solenoid. Pictures included.
Internal vs external vacuum source
- Thread starter AKrum
- Start date
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Rat Bastid
Dunamis Metron
If I’m reading your post correctly that hose in the picture is for the vacuum advance.
Professor Fate
Push the button, Max...
An electric choke doesn't require vacuum, it's electric... wired to keyed hot.
Yes 600 cfm model 4160
Vacuum sources are like this.
There usually is another small manifold vacuum port on the front of the carburator's baseplate.
The three threaded holes are for mounting a choke.
The circled hole is the location for the choke qualification passage. That's a vacuum source that opens the choke further when the engine starts running. Whether it is drilled through, you'll have to check.
I've also seen some older Holley's use that as part of a hot air supply to the choke. I doubt yours has that function.
the options through Holley for the conversion kits are either internal source or external source.
Yes, indeed has a front vacuum port. That should make it external sourced, correct? I guess whoever installed the carb missed that. Thank you for the help!
Its an external vacuum source.
But its probably unneccesary to use it as it looks like your carb has a port for that purpose.
Professor Fate
Push the button, Max...
Ah, I get you now- I misunderstood the question. Mattax has you covered.
Great! That answers it! Thank you for taking the time to answer!
Sure.
Looking at Holley's website and the instructions, it would seem that carb original was sold with an electric choke.
So that internal passage should be there.
Holley 0-80457S 600 CFM Street Warrior Carburetor
If your car originally came with an electric assist choke, you can probably use that same connection. I don't know how much current Holley's electric choke draws but it will add some load to the run circuit.
69FBCuda
Stand back 10' for your viewing pleasure & Safety
Not really sure what vacuum has to do with the choke plate. That's what they would call a hypercharger closed at full vacuum and open at no vacuum, empty your gas tank real quick.
67Dart273
Well-Known Member
The vacuum originally pulled heat from a tube down in a hot area of the manifold, heat from there in through the choke thermostat, and into a port matching the choke housing into the carb. The HEAT warmed the CHOKE THERMOSTAT
The heat pickup tube "originally" had a tube connecting one end of the tube to the open area "bonnet" above the carb to give it clean air and keep out debri. The tube then made a sort of U turn down into the hot area of the manifold "well" and back up to the choke thermostat
Random photo off the internet, Chev:
Some Fords went clear down to the exhaust manifold and back up
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That's different. That brings exhaust heat to an integral choke.
AFAIK the passage on the side of the 41450/60 main body was intended to bring manifold vacuum to a qualifying piston inside the choke housing.
Same job as the external vacuum diaphram on this carb
In this illustration it works with spring and vacuum, which explains the spring on the Motorcraft 2150 in the photo above.
More About Carburetors (Session 223) from the Master Technician's Service Conference
AFAIK the passage on the side of the 41450/60 main body was intended to bring manifold vacuum to a qualifying piston inside the choke housing.
Same job as the external vacuum diaphram on this carb
In this illustration it works with spring and vacuum, which explains the spring on the Motorcraft 2150 in the photo above.
More About Carburetors (Session 223) from the Master Technician's Service Conference
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