Who knows 2 barrel carbs ?

-
P

pearljam724

Well-Known Member
Joined
Aug 29, 2019
Messages
466
Reaction score
203
Location
United States
This nipple i’m pointing at with a screwdriver, under the fuel inlet. I assume this is an additional vacuum port ? This wasn’t hooked up when I bought my car and I can’t find anywhere on line where this was originally routed to ? Anyone know ? 73 Dart 318 with stock manifold

3A92D3C8-CD74-40DB-A15A-8946B7C33ADC.jpeg
 
pearljam724 said:
This nipple i’m pointing at with a screwdriver, under the fuel inlet. I assume this is an additional vacuum port ? This wasn’t hooked up when I bought my car and I can’t find anywhere on line where this was originally routed to ? Anyone know ? 73 Dart 318 with stock manifold

View attachment 1715570660
Click to expand...


That's a source for manifold vacuum....

If you don't need to use it, just cap it off... Or you can connect a vacuum gauge to it and it's good to use to see engine vacuum and if you drive for highest vacuum, you will get maximum MPG...

Now the other nipple on the top left of the picture is a source for ported vacuum and should be connected to the vacuum advance pod from the distributor... Ported vacuum is what the distributor vacuum advance needs to work properly...
 
krazykuda said:
That's a source for manifold vacuum....

If you don't need to use it, just cap it off... Or you can connect a vacuum gauge to it and it's good to use to see engine vacuum and if you drive for highest vacuum, you will get maximum MPG...

Now the other nipple on the top left of the picture is a source for ported vacuum and should be connected to the vacuum advance pod from the distributor... Ported vacuum is what the distributor vacuum advance needs to work properly...
Click to expand...
Thank you. As you stated I have my vacuum advance hooked up to the one on passenger side of carb as you pointed out. If the one I pointed out wasn’t plugged, what problems would that have caused ?
 
Rough idle, bad mileage, generally running like crap.
 
That is the canister purge port. Before deciding "URRGH! SMOG CONTROL BAD! HULK SMASH!", you might want to read up on it.

Beyond that, carburetor operation and repair manuals (including for the Carter BBD, which is what you have here) and links to training movies and carb repair/modification threads are posted here for free download.
 
pearljam724 said:
If the one I pointed out wasn’t plugged, what problems would that have caused ?
Click to expand...


Vacuum leak and poor performance/sluggish/stumble... Not to mention run lean which is bad for an engine extreme lean can burn a hole in a piston...
 
krazykuda said:
Vacuum leak and poor performance/sluggish/stumble... Not to mention run lean which is bad for an engine extreme lean can burn a hole in a piston...
Click to expand...
Does anyone know if the tiny linkage clips can be found at a hardware store ?
Damn me, I lost one. I know Ebay sells them.
 
Need some more help guys. Disregard last post. I found some clips When I hook a vacuum gauge up to the port I questioned. I get no vacuum reading ? No vacuum reading hooked up to the passenger side port that the distributor advance hooks up to either ? Why am I not getting a vacuum reading ? The gauge works fine when I suck on the hose, so it’s not the gauge.
 
The sparkport only begins to read vacuum as the throttle is opened. By 2000 rpm you will have a good reading on the spark port.
The full time port should have vacuum all the time..... unless the wrong gasket is installed or unless it was installed backwards.
 
AJ/FormS said:
The sparkport only begins to read vacuum as the throttle is opened. By 2000 rpm you will have a good reading on the spark port.
The full time port should have vacuum all the time..... unless the wrong gasket is installed or unless it was installed backwards.
Click to expand...
I don’t know buddy. No vacuum reading at vacuum advance port or under fuel inlet. There is a Y adapter inserted into the stock manifold that the brake booster connects to and of course I have vacuum reading there. Nothing on carb itself. There’s also a port on the carb that the stock egr valve attaches to. Vacuum no where on carb. Weird
 
Think mine was connected to the flapper valve in the air cleaner. Warm air intake for those damp days at 55 degrees.

should pull carb and see why that port has no vacuum,as well as the other one.
 
blow through the 'ported' vacuum port, you should be able to blow out somewhere, ideally right above the throttle plate. here is some info from a jeep board and a BBD
On the Stock Carter BBD or Carter-Weber BBD like mine, the drivers side back corner nipple goes to the air filter TAC (hot air flaps). The big driver's side port on the bottom goes to the power brakes. The center back big one goes to the PCV with a T fitting for the canister purge. If you have a solenoid on this line, toss it as a recall, only leave the T for the canister purge. Back passenger side to choke pull off. The valve cover side center goes to the distributor. It 'can' T for the CTO feed 'or'.. The front drivers side corner one goes to the CTO valve. From the CTO, a line goes to the canister purge signal 'and/or' one can be fed off this purge line to the air filter TVS and from there to the EGR.
 
pearljam724 said:
I don’t know buddy. No vacuum reading at vacuum advance port or under fuel inlet. There is a Y adapter inserted into the stock manifold that the brake booster connects to and of course I have vacuum reading there. Nothing on carb itself. There’s also a port on the carb that the stock egr valve attaches to. Vacuum no where on carb. Weird
Click to expand...
Some years used venturi vacuum to purge the vapor canister or to signal the EGR thru a vacuum amplifier that looks like a small ball about 4inches in diameter, usually mounted on the valve cover.
AJ/FormS said:
The full time port should have vacuum all the time..... unless the wrong gasket is installed or unless it was installed backwards.
Click to expand...
You may have to separate the baseplate off to verify the gasket is correct.

OOPs, Pishta already straightened it out.
 
You must log in or register to reply here.
-

Back
Top