Anyone have 2 barrel carb ?

-
P

pearljam724

Well-Known Member
Joined
Aug 29, 2019
Messages
466
Reaction score
203
Location
United States
I just bought a 73 Duster with a 2 barrel 318 a couple day’s ago. The previous owner installed an aftermarket Carter BB 2 barrel I believe. I’m just getting familiar with this carb and intend to leave the car as a 2 barrel. I worked out some bugs and an improper choke adjustment, etc. Car is running a lot better now. I wanted to verify this vacuum hook up. It is attached from the side of carb to the top fitting on this mechanism in the passenger corner of firewall. What is this mechanism ? The vacuum advance on distributor is hooked up to the bottom port of that same mechanism. I want to verify previous owner has this hooked up properly. I worked out all of the bugs and tuned the carb properly. It’s now running a lot better. Where prior to me going over it. It would stall and shut off once it was warm and sputter under acceleration. The choke wasn’t opening completely once warm. The V shaped rod connecting the choke vacuum to choke rod needed squeezed tighter together to take out the slop on this choke set up. Can someone verify these vacuum connections being correct or not ? Lastly, what is the connection that is plugged in the 4th picture ?

7F00D4CD-E677-4CD1-82C3-550EE84D3632.jpeg


81C8229F-0A36-4025-B715-C846C4130131.jpeg


327B1087-8BED-4DFA-8D97-E7CCEFBCF070.jpeg


F1AC8AFA-F524-4A9E-9B47-24B23346939C.jpeg
 
Osac/nox valve. From what I gather the orifice spark advance control is used to delay distributer vacuum advance during acceleration. On my Duster that device is mounted to the side of the air cleaner housing. Sorry, but I don’t have a clue about the rest. My carb doesn’t have that forward fitting you’re pointing to in the last photo.
 
Last edited:
The last photo is the bowl vent. It shouldn’t be capped off like that. The earlier carbs just vented into the air horn, but those went to a charcoal can or something
 
The OSAC valve on the firewall should be bypassed; these are notorious for causing stumble and mushy acceleration. They were put there to squeak the new '73s past their Federal emissions type-approval tests so the cars would be legal to offer for first sale. Run the vacuum hose directly from the nipple in the centre of your first pic, to the distributor vacuum advance. No need to cap or loop the OSAC valve itself.

As jas0162 correctly says, the bowl vent should definitely not be capped. If a previous owner hacked and pillaged the vapour canister system, put it back together as described here; this system gives multiple benefits and zero drawbacks.

Beyond that: Carburetor operation and repair manuals and links to training movies and carb repair/modification threads, including for your Carter BBD, are posted here for free download.
 
jas0162 said:
The last photo is the bowl vent. It shouldn’t be capped off like that. The earlier carbs just vented into the air horn, but those went to a charcoal can or something
Click to expand...
That makes sense and sounds accurate. You could probably route it to a tank return line to help with vapor lock.
 
pearljam724 said:
You could probably route [the carb bowl vent] to a tank return line
Click to expand...

No, that would be wrong. We don't get to just randomly connect this thing to that thing, or this hose to that line. Not if we want the car to run and operate correctly. Not if we want to avoid creating extreme safety hazards.

Doing the job right yields better results, and is no harder than doing it wrong.
 
It looks like a wire goes to the electric choke, you might want to check voltage there to make sure it is correctly wired and functions.
 
dibbons said:
It looks like a wire goes to the electric choke, you might want to check voltage there to make sure it is correctly wired and functions.
Click to expand...
I believe you’re right. The choke is opening properly now after the engine warms up. But, it doesn’t close on its own after the engine is not running or cooled off. I have to close it by hand, after the car has sat. I don’t know how to address, test or fix that issue. These 2 barrels are strange creatures compared to modern 4 barrels.
 
Post #1 photo #3, looks like the kick down lever spring is not correct. Check you FSM.
 
Do yourself a large favour: remove the existing choke thermostat and its modulator (at the other end of that wire) and install a № 1274 Electric choke kit. For one thing, it's adjustable, which the factory choke is not. Also, it is not dependent on the exhaust pass-thru in the intake manifold being free of carbon blockage, nor is it dependent on your manifold heat control valve working correctly. Once installed and adjusted, this electric choke kit will make the car a whole lot less cold-blooded than can be hoped for with the factory choke.

(Another large favour: put in a set of NGK № ZFR5N projected-electrode spark plugs, which move the spark away from the quenchout area of the cylinder head and will also go a noticeable way toward making the car less gaspy. Yes, they will fit and work; no, they won't hit the pistons or anything.)
 
Dana67Dart said:
Post #1 photo #3, looks like the kick down lever spring is not correct. Check you FSM.
Click to expand...
Kick down lever is functionally correct. I do have to rearrange the springs to keep them from riding on one another. But, they are functioning correct.
 
Last edited:
slantsixdan said:
Do yourself a large favour: remove the existing choke thermostat and its modulator (at the other end of that wire) and install a № 1274 Electric choke kit. For one thing, it's adjustable, which the factory choke is not. Also, it is not dependent on the exhaust pass-thru in the intake manifold being free of carbon blockage, nor is it dependent on your manifold heat control valve working correctly. Once installed and adjusted, this electric choke kit will make the car a whole lot less cold-blooded than can be hoped for with the factory choke.

(Another large favour: put in a set of NGK № ZFR5N projected-electrode spark plugs, which move the spark away from the quenchout area of the cylinder head and will also go a noticeable way toward making the car less gaspy. Yes, they will fit and work; no, they won't hit the pistons or anything.)
Click to expand...
Thank you on the choke kit reference. I don’t think mine is working. If I’m not mistaken. I believe the choke is supposed to close on its own if it’s working properly , once the engine cools off. Which it’s not. The vacuum choke pull is working properly.
 
Has anyone found the carbsonly website Dan recommended for electric choke purchase, my search shows page not found?

I did find a mikes carb youtube video, not sure if the parts are the same:
 
How about this nipple under the bowl i’m pointing at with screwdriver ? There was nothing hooked up here when I bought my car. I assume it’s vacuum, but there is a vacuum port on the back for the brakes. So, I’m not sure ? Never mind, everything else. I have the whole engine bay tore apart.

7FC86DFE-7C02-4033-96DC-FD402511658E.jpeg
 
You must log in or register to reply here.
-

Back
Top