All Small Six Carter rbs carburetor

This relates to all small sixes
Trey Stanaland

Trey Stanaland

New member
I need help with this carter rbs carburetor! To give some back story into this, one of my friends bought a 1970 Mustang coupe with the 250 I6 about a year ago. Since he is in the military the task of fixing it came to me. I got it running but the idle screw did little to nothing I rebuilt the carb and still no change. So I bought a new rbs carburetor from ebay which had good reviews. I put it on and it would not stay running I had to hold the throttle down while holding the choke open. The choke just tried to stay closed the whole time and the linkage would not flip the choke open. Some of the brass plugs on the carb leaked gas. The previous owner i assume done away with the automatic choke on this mustang. The choke on the old carberator was broke so i had to pour gas into it. Should I put the automatic choke back in service. And if not could I put a manuel choke on it? I'm at a standstill and need all the help I can get ,any and all help is appreciated.
 
Trey Stanaland said:
the idle screw did little to nothing
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This almost always indicates that there is a vacuum leak somewhere. Have you checked all the vacuum lines to ensure that they are intact and not leaking (including the one that goes to the automatic transmission, is so equipped)?

Trey Stanaland said:
I need help with this carter rbs carburetor! So I bought a new rbs carburetor from ebay which had good reviews. I put it on and it would not stay running I had to hold the throttle down while holding the choke open. The choke just tried to stay closed the whole time and the linkage would not flip the choke open. Some of the brass plugs on the carb leaked gas.
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The aftermarket ebay carburetors are, in my limited experience, a crap shoot. The one I bought from eBay wouldn't even allow the engine to start. I finally bought one through Rock Auto (https://www.rockauto.com/en/catalog...+250cid+l6,1132456,fuel+&+air,carburetor,5904), which comes from a company in Canada (Autoline) that refurbishes them. Even at that, the first one I got had a warped base and had a vacuum leak that I couldn't fix. I was able to exchange it and the replacement works well. If you can return the eBay one you bought I'd suggest you do that and get one from Rock Auto.
Trey Stanaland said:
The previous owner i assume done away with the automatic choke on this mustang. The choke on the old carberator was broke so i had to pour gas into it. Should I put the automatic choke back in service. And if not could I put a manuel choke on it? I'm at a standstill and need all the help I can get ,any and all help is appreciated.
Click to expand...

Tell us more about the choke - how is it broken? Also, I'm a little confused about how you have the choke hooked up. There's supposed to be a tube that runs to the exhaust manifold. It brings hot air (not exhaust gas) up to a fitting on the carb, which conducts that air into the choke assembly and operates on a mechanism to open the choke. It will take a little while (minutes) for that all to work before the choke opens. Did you have that all hooked up correctly?
 
John Ha said:
This almost always indicates that there is a vacuum leak somewhere. Have you checked all the vacuum lines to ensure that they are intact and not leaking (including the one that goes to the automatic transmission, is so equipped)?





The aftermarket ebay carburetors are, in my limited experience, a crap shoot. The one I bought from eBay wouldn't even allow the engine to start. I finally bought one through Rock Auto (https://www.rockauto.com/en/catalog...+250cid+l6,1132456,fuel+&+air,carburetor,5904), which comes from a company in Canada (Autoline) that refurbishes them. Even at that, the first one I got had a warped base and had a vacuum leak that I couldn't fix. I was able to exchange it and the replacement works well. If you can return the eBay one you bought I'd suggest you do that and get one from Rock Auto.





Tell us more about the choke - how is it broken? Also, I'm a little confused about how you have the choke hooked up. There's supposed to be a tube that runs to the exhaust manifold. It brings hot air (not exhaust gas) up to a fitting on the carb, which conducts that air into the choke assembly and operates on a mechanism to open the choke. It will take a little while (minutes) for that all to work before the choke opens. Did you have that all hooked up correctly?
Click to expand...
 
The automatic choke seems to be done away with by the last owner cause there's a plug in the hole on the manifold. I was under the impression that the throttle linkage was supposed to open the choke? I have not checked all the vacuum lines like the one to the transmission. But there is a second nipple on the outer side of the vacuum advance that I haven't been able to figure out where it would go(one side goes to the carberator nothing on the other side).I just thought since the throttle wasn't tripping the choke that something was messed up? How would I hook up the automatic choke just take out the plug in the manifold get some sort of tubing and a flare nut kit for where it connects into the carberator? And I appreciate the questions and help!
 
These are the 1970 Ford Mustang Vacuum Line Routing Diagrams for a 250 Six with DVCV

1970 Ford Mustang Vacuum Line Routing Diagrams for a 250 Six without DVCV

This should help you to figure out your Second Vacuum Line to the Distributor Duel Vacuum Hook Ups one closest to the Cap is a Retard Feature. Good Luck. Edited
 
bubba22349 said:
These are the 1970 Ford Mustang Vacuum Line Routing Diagrams for a 250 Six with DVCV




1970 Ford Mustang Vacuum Line Routing Diagrams for a 250 Six without DVCV




This should help you to figure out your Second Vacuum Line to the Distributor Duel Vacuum Hook Ups one closest to the Cap is a Retard Feature. Good Luck. Edited

I appreciate it gonna need all the luck I can get!
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Here's some pictures of the engine and carberators.
 

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Thank you for the pictures Trey Stanaland, they do help alot. So first off the Distributor Advance likely isn’t hooked up correctly. The front Advance Canister Port isn’t hooked up at all and it should be hooked up direct the Carbs Ported Distributor Vacuum source. The Rear Port that appears to be hooked up is for a Timing Retart Feature and would be hooked up to a 3 port Coolant Temp Control Mounted on the Upper Radiator Hoses Thermostat Housing. The Top coolant temp Control port goes to that rear distributor advance canister port the bottom port of the coolant temp Control, the middle port is capped off. Is that how it is hooked up? Edited
 
The picture of the intake where the one port has a rubber cap then the other goes to the transmission then below that on the exhaust it has a piece of crimped line that I would assume would go to the carberator for the automatic choke. Then on the distributor picture the rear port has no hose or line its just the port then the one closest to the distributor cap went to the side of the carberator l. I know nothing about the 3 port temp control unless that is what is on the intake manifold. How would I redo the automatic choke just a piece of tubing and a flare nut for the carb?
 
Trey Stanaland said:
The picture of the intake where the one port has a rubber cap then the other goes to the transmission then below that on the exhaust it has a piece of crimped line that I would assume would go to the carberator for the automatic choke. Then on the distributor picture the rear port has no hose or line its just the port then the one closest to the distributor cap went to the side of the carberator l. I know nothing about the 3 port temp control unless that is what is on the intake manifold. How would I redo the automatic choke just a piece of tubing and a flare nut for the carb?
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Only part hooked up right on the Manifold Vacuum T is the one that goes to the Transmission Vacuum Modulator and the other Capped off Port. Nothing form that T will go to the Carb or the Carb Choke hook ups. The Carb gets all of its own Vacuum needs internally through the Carb Base Mounting.
 
Some of the Carb Distribitor Vacuum Line Hookups are in this older site Post. https://fordsix.com/threads/carter-rbs-vacuum-ports.77375/

The Carbs Choke Hook ups are fairly simple the main one is that plugged off Exhaust port up to the Choke Housing to heat the Thermostatic Spring that opens the Carbs Choke Blade (a Heat Stove Pipe) it will need to be replaced in order to work correctly. Auto Parts Stores have a universal repair kit made for these in the HELP Parts Section. There may also be a second pipe that goes down to the bottom of the exhaust Manifold this hooks up to the stock Air Cleaner Base to bring clean filtered air that is drawn into the Choke Stove Pipe.
 
I don't know if these will help with your choke but I took a couple photos of mine
 

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This Monday I'm gonna try to get the stuff to put on the automatic carb into working function. I'll update yall then. I do wanna day again I appreciate yall helping me I think we may have this thing fixed!
 
Trey Stanaland said:
Here's some pictures of the engine and carberators.
Click to expand...
Trey, welcome. The vacuum line to the distributor is wrong. Move the black vacuum line from the inner nipple on the dist to the outer nipple. this will not help your carb issue, but will greatly help engine efficiency and response. If the manifold heat choke is not being used, plug the threaded inlet on the choke housing, that will be a vacuum leak.
 
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