Vacuum Routing to Carburetor - Ford Truck Enthusiasts Forums

Notices
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

Vacuum Routing to Carburetor

 
  #1  
Old 03-14-2019, 06:29 PM
BlueWhiteFord's Avatar
BlueWhiteFord
BlueWhiteFord is offline
New User
Thread Starter
Join Date: Feb 2019
Posts: 19
BlueWhiteFord is starting off with a positive reputation.
Vacuum Routing to Carburetor

Thanks to everyone giving amazing advice and information on this forum, I have been able to fix almost everything and install my carburetor today. Everything worked fine until it was time to connect the hoses to the carb. I have been able to re-attach the ones that were still on the old carburetor, but there are a few ports on the carburetor that I do not know where they should go to, nor do I have a hose that I could attach to those ports.
I attached what I could and tried starting it. Fired right up, but even after turning the idle screw all the way out and the mixture down, it still idled fast, what led me to believe that some of those ports might be important to the vacuum system.

Below I have some pictures of the carburetor and the ports I am talking about. If anyone could tell me what those ports should be connected I would be extremely grateful.


This port is on the front driver's side of the carb

This port is on the back drivers side


The upper one seems to be the PCV valve attachment since it runs to the passenger side valve cover. The lower one is attached to the steel line that comes out of the engine. (The crappy hoses are just placeholders)
 
  #2  
Old 03-14-2019, 07:21 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 43,118
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future


The steel line coming out of the manifold should curve around and hook to that brass nut fitting going to the choke housing.

The fuzzy braided hose coming out of the manifold should go up to that port that you said was for the PCV valve.
 
  #3  
Old 03-14-2019, 07:23 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 43,118
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future


Fuzzy hose goes to this port that goes to the air cleaner area right under the air horn of the carb.
 
  #4  
Old 03-14-2019, 07:28 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 43,118
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
When you are tuning the carb, make sure the choke door on top is fully open. If it's shut any at all, it can cause a high idle.

Back your idle stop screw out till the idle slows down. If you can't get it slow enough, pull the vacuum line off the distributor while it's running. See if that line has vacuum. It should not. If it does, you may have it plugged into the wrong port.
 
  #5  
Old 03-14-2019, 07:56 PM
BlueWhiteFord's Avatar
BlueWhiteFord
BlueWhiteFord is offline
New User
Thread Starter
Join Date: Feb 2019
Posts: 19
BlueWhiteFord is starting off with a positive reputation.
Pretty sure the fuzzy hose and the and that metal line were in the place that they are in now on the old carb. Do they serve the same purpose? They both come out of the manifold. I have the PVC valve hooked up to the black hose on the driver's side. I just don't know what to hook up to the other two ports that are empty on the picture.
 
  #6  
Old 03-14-2019, 08:14 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 43,118
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
That fuzzy hose and the metal line route into the manifold to a "stove" or heat area. That brass nut coming out of the choke housing should be sucking air unless it's been plugged.

Filtered air comes down from the aircleaner through the fuzzy hose, and goes into the stove area where it's heated. It then continues out of the stove on the hard steel line and goes up to the choke housing where that nut is located. That is the reason it's sucking vacuum, it's pulling warm air into the choke housing so the choke will open up as it warms up.
 
  #7  
Old 03-14-2019, 09:47 PM
matthewq4b
matthewq4b is online now
Postmaster
Join Date: Feb 2008
Location: St Albert, Alberta
Posts: 3,120
matthewq4b is a name known to allmatthewq4b is a name known to allmatthewq4b is a name known to allmatthewq4b is a name known to allmatthewq4b is a name known to allmatthewq4b is a name known to all
Originally Posted by Franklin2 View Post
That fuzzy hose and the metal line route into the manifold to a "stove" or heat area. That brass nut coming out of the choke housing should be sucking air unless it's been plugged.

Filtered air comes down from the aircleaner through the fuzzy hose, and goes into the stove area where it's heated. It then continues out of the stove on the hard steel line and goes up to the choke housing where that nut is located. That is the reason it's sucking vacuum, it's pulling warm air into the choke housing so the choke will open up as it warms up.

I think you have this backwards Dave. The fuzzy hose (it is actually sheath insulation) goes to the choke housing. That sheath is there to insulate the pipe to help prevent heat loss.
The other pipe the beside the above in the intake goes to the Carb top plate and draws filtered air in to be heated and then fed to the choke housing.

The other 2 ports are emissions ports. The front one should be evap purge control and the back one should be EGR.
 
  #8  
Old 03-15-2019, 10:11 AM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 43,118
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
Originally Posted by matthewq4b View Post
I think you have this backwards Dave. The fuzzy hose (it is actually sheath insulation) goes to the choke housing. That sheath is there to insulate the pipe to help prevent heat loss.
The other pipe the beside the above in the intake goes to the Carb top plate and draws filtered air in to be heated and then fed to the choke housing.

The other 2 ports are emissions ports. The front one should be evap purge control and the back one should be EGR.
Thanks for the correction.
 

Thread Tools
Search this Thread

Contact Us About Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.