Carburetor Troubles
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Freshman User
Joined: Mar 2009
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From: Illinois
Carburetor Troubles
I have a 78 F250 with 300 I-6 I just rebuilt the carter carb 1 barrel. I installed it today, truck fired ran and in the process it started shooting fuel out of the line next to the filter on the carb. the filter fuel inlet is on the passenger side and the line that was pooring fuel out is on the drivers side What is this line it was previously blocked off before? So i blocked it off again and then it shot fuel out the vent tube on top of the carb. What causes this im personally leaning towards a bad float. Float was not replaced, but this was my first carb rebuild and am kind of lost a bit i wasn't wanting to jump the gun on anything. This carb also has 3 or 4 what i assum vacum lines coming off the carb and they were all blocked off before, but the truck ran good before this, i blocked them off again like they were before i rebuilt the carb and i have no clue where they go, or if i need them. Any input is greatly appreciated. Im a bit lost. P.S. Reason for rebuild was truck sat for a few years i figured it couldn't hurt also replaced the fuel pump and rubber hoses.
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Joined: Jan 2000
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From: Cullman Alabama
At one time, in the public library you could find Vacuam diagrams for almost any vehicle made in the U.S.
It sounds like you have an Emissions carb from a newer pickup or car. That same carb can be found on a lot of different engines. I got one off a Jeep Mail truck.
The smallest of those lines should go to the Distributor vacuam advance. You may have an advance and Retard supply from that carb.
On some early 80's there were vacuam lines going to a thermal switch up on the Thermostat housing and some other features.
Are you certain you have the float adjustment set correctly?
It sounds like you have an Emissions carb from a newer pickup or car. That same carb can be found on a lot of different engines. I got one off a Jeep Mail truck.
The smallest of those lines should go to the Distributor vacuam advance. You may have an advance and Retard supply from that carb.
On some early 80's there were vacuam lines going to a thermal switch up on the Thermostat housing and some other features.
Are you certain you have the float adjustment set correctly?
Elder User
Joined: May 2008
Posts: 508
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From: Wasilla, AK
Did you have a ID tag on the carb? If you do your parts man can cross reference the numbers to see what year carb you have. Thudpuker is right Ford had a lot of applications for these one barrel Carters. Sounds like overflow problem is the float level is set to high? Read the carb kit instructions real close on setting the float level.
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Freshman User
Joined: Mar 2009
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From: Illinois
I'm going to end up buying a new float do you think id need another rebuild kit i don't think the gaskets would be too messed up it only had maybe 20 ounces of fuel run threw it? but something for me to tinker with on a sunday in the garage it's supposed to be 60 so sounds fun. i am going to tap on the carb a bit and see if the float is just stuck and hopefully that will work but you never know ... i know its the wrong forum but can you guys point me in the right direction for identifying my axles?
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Joined: May 2002
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That tube is for the Charcoal evaporate canister. If you vehicle is equipped, you will have a vacuum line that is slightly smaller than a brake booster line.
To have gas coming out of it, your float is either set WAY to high, or the very small parts to shut the fuel off is shot.
Did you remove the float at all when you rebuilt the carb? If not, it's real easy. There is a pin holding the float on, gently pull it out AND SET IT SOMEWHERE SAFE. It's not a standard part in the kit. You will see a brass fitting that looks like a very large flat tip screwdriver fits into. Inside of it is more small brass pieces, and a very small spring. These are in the kit. The one piece has a rubber tip that wears out, and no matter where you set the float, the flow will not be shut off.
There is a small screen on the bottom ot the larger brass peice {or should be, if not, don't sweat it}. CAREFULLY clean it and the hole that these parts go in.
You never mentioned if you changed out the acclerator pump. It is in this area also under 2 springs and a plate with 4 screws. Take care of it while your in there.
It's a really simple carb, and don't panic if you don't have the right carb id #, the kit covers about a gazillion different id #'s, including International Harvester!!
To have gas coming out of it, your float is either set WAY to high, or the very small parts to shut the fuel off is shot.
Did you remove the float at all when you rebuilt the carb? If not, it's real easy. There is a pin holding the float on, gently pull it out AND SET IT SOMEWHERE SAFE. It's not a standard part in the kit. You will see a brass fitting that looks like a very large flat tip screwdriver fits into. Inside of it is more small brass pieces, and a very small spring. These are in the kit. The one piece has a rubber tip that wears out, and no matter where you set the float, the flow will not be shut off.
There is a small screen on the bottom ot the larger brass peice {or should be, if not, don't sweat it}. CAREFULLY clean it and the hole that these parts go in.
You never mentioned if you changed out the acclerator pump. It is in this area also under 2 springs and a plate with 4 screws. Take care of it while your in there.
It's a really simple carb, and don't panic if you don't have the right carb id #, the kit covers about a gazillion different id #'s, including International Harvester!!
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Joined: Dec 2007
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From: Boise, Idaho
I second this. The tube on the right (next to the fuel inlet) is a vapor release port to let fumes out of the carb. If you have fuel coming out of that, your float is set WAY WAY wrong, or a needle inside was set incorrectly or damaged.
It's generally a good idea to replace your float while you're in there. They're like $4 - $5, and will go bad over time. If they're bad, they'll sink to the bottom of the carb and will continually let fuel in until it fills the carb and pours out of the top. Your carb kit should have the description of how to properly set the float. Also, if as mentioned above, the seat on the needle right where the fuel comes in is bad, the fuel pump will keep filling your carb with gas because nothing is blocking it off.
Either way, you'll need to open up your carb again. If you do it right, you can do this while it's on the vehicle and only remove the top. Just be sure to line up everything when you put the top back on. The three things to watch out for are the choke linkage in the back (make sure the metal arm hanging down goes back into the slot), the choke heat tube (it goes into a divet in the exhaust manifold), and the big Y arm on the front of the carb (it goes around the little arm right next to the vent tube mentioned above.)
It's generally a good idea to replace your float while you're in there. They're like $4 - $5, and will go bad over time. If they're bad, they'll sink to the bottom of the carb and will continually let fuel in until it fills the carb and pours out of the top. Your carb kit should have the description of how to properly set the float. Also, if as mentioned above, the seat on the needle right where the fuel comes in is bad, the fuel pump will keep filling your carb with gas because nothing is blocking it off.
Either way, you'll need to open up your carb again. If you do it right, you can do this while it's on the vehicle and only remove the top. Just be sure to line up everything when you put the top back on. The three things to watch out for are the choke linkage in the back (make sure the metal arm hanging down goes back into the slot), the choke heat tube (it goes into a divet in the exhaust manifold), and the big Y arm on the front of the carb (it goes around the little arm right next to the vent tube mentioned above.)
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Freshman User
Joined: Mar 2009
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From: Illinois
Thanks for all the help with that everyone I just ordered a new float it will be here in a couple of days as for the carb that was the only thing that wasn't replaced, i'll remember that for the next time i rebuild a carb. REPLACE EVERYTHING.