So this is a continuation of the last thread I made involving no power from the ignition coil. I fixed that by simply replacing it and therefore getting spark to all my plugs, however it's still not starting....I've converted it from tfi to ds2 it's an 85 f 150 302 manual trans. Now I'm down to narrowing down vacuum leaks. I've installed the PVC valve and connected it to a port on the back of the carb. I have a vacuum line running from the back of the manifold to the brake booster, and a line running from the passenger side port to the dizzy, my heater is all mechanical, and I do not have cruise control. As of right now, those are the only vacuum lines I have hooked up. There are several ports on the back of the intake that I'm not sure what they are for or where they go or if they should be capped or not, 3 ports left on the carb, and 2 hoses coming off of the spacer under the carb connected to the egr valve, there will be pictures to come...

 

One of the mystery hoses and the port on the carb

 

Two more empty ports on the carb

 

Back of Intake manifold, big hose goes to brake booster, one hose goes from inside and connects to the other, one hose is plugged and one port is empty...

 

In picture one, that outlet on the carb should go to the charcoal canister. There are usually two or more parts in between there and the canister in the line. I forgot their names. The second one is fresh filtered air. Usually supplied air for the stove pot to heat the choke, but I am not sure on your year. If for stove pot, there would be a steel line to the bottom of the exhaust manifold on the pass side that hooks up to it. The a metal tube would come out of the top of the exhaust manifold and end up near the choke. Picture three is of the main vac tree. Used to supply contact vacuum, If you do not need it, then cap it. Also, do you have the vacuum diagram still on the radiator support? That should outline everything from the factory.

 

Yes, what bcamill said - bowl vent on the carb, automatic choke heat riser stuff, block off any unused hoses or ports.

I have no idea what that hose is you're showing us in the first picture; where does the other end go? Plug it if unsure, at least for now....

 

All unused [open] ports should be capped.

 

Post #2 pic
-Large top one with the bend in it is the fuel bowl vent, do not plug. If you don't have a charcoal can to run it to just get one of those little plastic fuel filters to hang off it to keep trash out of it. If you've ever messed with a non-emissions Holley the bowl vents are on top pointing straight up inside the air cleaner housing so they stay clean that way.
-The one pointing straight up with the cap on it is some kind of temperature compensated assist for the power valve. OK to leave it open or plugged if you don't have the right stuff to run it (which I don't know how).
-The hose in your hand might go to the power valve if nothing is hooked to the power valve now. It is the port on the very bottom of the carb pointing straight ahead underneath the valve listed above.

Post #3
-The one with the bend in it at top I believe hooks to the choke pull down diaphragm which I don't see in your pics so plug it.
-The other open one at the bottom is not a vac port but is just the hot air hook up for the choke which if yours is like most has rotted off the exhaust manifold. Not really needed, the electric choke works pretty good....and you need to have the electric choke hooked up or the choke will never open. Leaving hot air port open is fine.

As mentioned, the vac "tree" on the back of the intake needs to have any open ports plugged. Also check the front of the carb mounting flange good as well. Dad's had two vac ports there, one on each front corner like the one in your first pic where you're holding the hose. There's also an EGR port on the front bottom corner that needs to be plugged. It's under the fuel bowl and points kinda towards the driver headlight and is hard to see.

 

Ok, thank you, I'm going to look into more about what you said with picture one, the diagram on the radiator support was longggg gone, and I don't have any tube coming out of the exhaust manifold, just a plug and wire for what was the O2 sensor leftover from it being tfi previously

 

Good stuff ssellers, thank you! When I sent the carb in to get it rebuilt, I got it back with many of the ports capped, the choke is manual btw if that makes any difference...

 

If you aren't using the original automatic choke you should cap off, or filter, the intake pipe into the choke housing (pic 2).

This is because there is vacuum running to that port, via a passage in the choke housing, from the carb. The vacuum originally pulled filtered air from under the air cleaner, which was then heated by the exhaust manifold, into the choke housing to warm the spring..........but now is pulling unfiltered air into the carb.

Alternatively you could use a vacuum hose to connect the two open ports together directly. Filtered air would then pass through choke housing to the carb as originally, but it will be unheated........no problem with a manual choke; & no dirt entering the engine.

 

And the correct fuel/air calibration will be maintained, as opposed to just capping the port on the choke housing! Good suggestion, Ken!

 

I like it ken!! I'll get all this stuff done this weekend and let you guys know how it works out! Thanks everyone!

 

I think you have that backwards.

A thermostatic "hot air" choke in conjunction with an electric assist is what Ford used on their Motorcraft carburetors from the early 1970s right up until fuel injection took over. Before that time, they didn't use the electric assist. The way it works is this:

Clean, filtered air from the air cleaner is pulled through the "fresh air" tube (a rubber hose that is connected to the carburetor air horn and attaches to an aluminum tube) and into the bottom of the choke stove chamber on the exhaust manifold, where the air is heated up when the engine is running. From there, the heated air goes back up through the insulated "hot air" tube (attached on the top of the choke stove chamber on the exhaust manifold) that connects to the choke cap. As the air gets hot, it relaxes the spring in the choke cap, which allows the choke plate to open up as the engine warms up to run on a leaner mixture.

The "electric assist" portion of the stock choke system does not work on its own like an aftermarket electric choke. In fact, it doesn't have to work at all in order for the hot air choke to be effective. (Again, the electric assist wasn't around before the early 1970s.) It is only there to "assist" the hot air choke in temperatures above 60 degrees, where it helps the choke come off sooner for cleaner emissions. It doesn't work at all when the weather is colder than 60 degrees. It connects from the spade on the choke cap by a wire that connects to the back of the alternator. This part of the choke is secondary, meaning the choke will work fine without it, but the choke will NOT work correctly without the thermostatic "hot air" choke system.

 

Yeah, I was wrong about part of that and Ken corrected me.

However, in regards to the OP's setup he had nothing on the hot air tube which is why I said he must have the electric portion hooked up (if nothing connected to the hot air) because with neither hooked up the choke would not open....you did not highlight that part in red about the tube maybe being rotted off the manifold. Moot point now since he's running a manual choke.

Since Dad's hot air tube was rotted off the manifold I set his up with the original ~7V electric only. It works correctly but has only been tested at around 70 degrees and up so far. At that temperature, it took about a minute or so for the choke to heat up enough to fully open and come completely off the fast idle cam and for the plate to fully open. With a cold start at 90 degrees it took maybe 20-30 seconds if that. We'll see how it does come winter. Before I did the Duraspark conversion on his, the hot air tube was already rotted off and the feedback carb was running on electric only and the choke still functioned in all weather....as far as I know. He's 400 miles away but never mentioned it staying at fast idle although it was drinking gas.
***Both of these carbs came from National Carburetor (about ten years apart) so I don't know if they swap out the choke coil. The both had vacuum choke pulloffs as well. I read up on the 60 degree temperature function and will just have to wait until winter to see if the choke functions like stock or not.

As an aside, has anyone hooked full 12V up to the choke to see how/if it would function? The ~7V original line hooked up to an Edelbrock carb with 12V choke on another truck functioned fine, however I did not leave it like that and ran full 12V to it.