Proper Vacuum hose routing

[Banjer Picker]

Switched back to the factory 2 barrel intake and motorcraft 2050 carburetor. Trying to track down what I believe to be vacuum issues. Does anyone have a diagram of the proper routing of all of the vacuum lines?

Do you have any feedback on odd places that you have had vacuum leaks that have caused idle issues?

 

[Steve83]

Use 3' of garden hose or a mechanic's stethoscope withOUT the hard probe (just pull the hose off & use it open) to listen around the idling engine for obvious hissing. There will be some coming from throttle plates which may be loud enough to hear outside the carb, but just create a temporary leak to learn what you're trying to find.

Some carbs have the port names cast into their bodies, so clean it & look CLOSELY. But there shouldn't be very many ports: maybe a couple for full manifold vacuum near the bottom (below the throttle plates), another about level with the plates (ported vacuum for the distributor) and possibly a big one near the top for fresh air to the choke heat system.

 

[Banjer Picker]

Thanks for the input Steve.

Maybe i'll inderstand better if ask it a different way.

Where does everyone have the front vaccum port (located under the fuel bowl) routed too? Where does everyone have the small port on the passenger side routed to (or is it capped)?
Would anyone with a motorcraft 2050 mind posting a good picture of the front, pAssenger and back side of an opperational carb?

 

[DirtDonk]

What year is your Bronco? And if post-smog, is all your stuff intact? Or is this just the simple stuff, like distributor advance?
Either way, are you running the dual or single diaphragm advance mechanism?

I probably won't know the answers to your question, but at least that info will help others to figure out the proper routing.

Paul

 

[Banjer Picker]

Hey Paul. It's a '73 w/ no smog stuff. Just a simple motorcraft 2050 2 barrel carb and factory intake manifold. I'm really just trying to determine which port on the carb to use from the distributor.

Crazy that there are multiple write ups on full EFI installs but there doesn't seem to be much info on the factory carb. Perhaps that would be like a big write up on "upgrading a D30". (Not much demand for it)

My assumption is that my problem is going to be a bigger vacuum leak somewhere (intake perhaps) rather than incorrectly routed hoses.

 

[DirtDonk]

There are some old writeups with pics on which port to use, but it's been so long I forget.
Easy to find out though, by simply putting your tube/hose on the available ports and determine which one(s) have vacuum at idle, and which one doesn't. For most EB's, you want the one that doesn't.

If you have the dual-diaphragm vacuum unit on the distributor, use just the front facing port. You can either cap off the rearward one, or just leave it open like many do. I capped mine originally, but my Duraspark distributor only had the one.

If you want the original routing, your '73 likely had multiple hoses routing between carburetor manifold vacuum, direct manifold vacuum (to a port or "tree" on the back of the intake), ported vacuum from the carb, and all run through another little timed diaphragm device mounted to the intake in the rear on the passenger side.
From there, two hoses came to the distributor advance can.

Since you say your stuff has been removed, that concoction was probably removed as well. So a single hose from your ported vacuum fitting on the carb to the distributor is all you need.

Lots of members here still use the stock carb, so someone should be able to tell you exactly which fitting is ported, or timed, vacuum.
In the meantime though, see if you can determine which one by feeling for vacuum at idle.

Paul

 

[Ovalis]

That vac. port under the fuel bowl is for EGR. If you're not running it, cap it. The port on the passenger side behind the choke mechanism goes to your vac. advance on the dist. If your dist has two ports, run full vac to the retard port on your dist coming from the back of your manifold. If your carb has a large vac port on the back of it, you need to attach that to your PCV valve.

 

[Steve83]

Buy a MityVac - they're relatively inexpensive & the manual includes thorough explanations of each vacuum system, and how to use the gauge on it. Once you unnerstan what the port is supposed to do, identifying it using the gauge will be easy.

 

[Banjer Picker]

Thanks for all of the input gang.