Hi all,

My 72 F100 (360/390) died today. Because I have been have on going fuel pump issues that is the first place I looked.

Pump was puming.

Fuel lines were clear all the way back to the tank.

So, I primed the carb a few times and got nothing past the bit of fuel I poured in.

Well, I took the breather off and noticed that there was a bit of fuel seaping from beneath the carb. I primed it again and actually saw the fuel leak out. I have never messed with a carb before and am very hesitant to start, but it lookes as though only four bolds hold it on. I could take the gasket out and replace it with a new one. Would that be the fix or what???

Thanks

Tony in New Mexico

 

If you put a new gasket it in, it should fix the leak. The worst case senario would be that the throttle body (the bottom part of the carb where the bolts are) is cracked, which would mean a bit more work. When you take the carb off to change the gasket, take a look at the bottom of it for cracks. Don't get let yourself get imtimidated about carburetors, they're really not that bad to work with, provided you don't get deep into the inner workings of one. If you do replace the gasket, make sure you slacken the bolts of gradually, as the throttle body (the bottom section of the carb) can crack. Also, make sure you take the throttle linkage off carefully, and know how to put it back. One more thing, be prepared for gas to leak out of the carb when you take it off, this is normal, just be prepared to clean it all up. If you replace the gasket and the problem isnt solved, the throttle body may be cracked. Have I missed anything guys?

 

Sounds like you hit it all.

 

If I find a crack, what then???

Tony

 

You'll either need to replace the carb or at least that bottom half of the carb body. If it's the standard 2bbl carb they're $60-70 at Pep boys.

 

I had a similar leaking problem, only my leak was from another gasket actually in the carb, as opposed to yours between the carb and intake. I never found the bad gasket so I bought a new Holley Street Avenger carb and have never looked back. The truck runs a million times better and should help with the fuel economy. If you do find a crack I would seriously consider a new carb, depending of course on your money situation, how much you use the truck etc.

 

Hi all,

OK, got the carb off and put the gaskets on and put everything back. Still wouldn't run longer than for the gas I used to prime it. I have one question and this may be silly, but when I took off the throttle body I noticed that one side was flat and the other was chambered. It fits on either way, which is proper, flat surface up or down?

Thanks,

Tony

 

Qman,

Those carbs at pep boys are they just install and go or do you have to know what you are doing??

Tony

 

Sounds like may have trash in fuel line possible or bad fuel pump or clogged fuel filter !!! Good Luck!!

 

OK Guys,

Here is what has happened so far. Being Saturday I decided to give fooling with a carb a shot, expecting that the truck would never run again the moment I touched it.

Got the gaskets on, still a leak. Took them off and repositioned a bit. Got the leak stopped.

Prmined the thing and go it to run for a couple seconds. After going through this a few times I figured something wasn't right. Took the whole thing off again and started over.

Couple hours later, still nothing happening past the point the primed fuel was used up. Called my rednecky brother in Fl and he told me something to try.

Figuring I had nothing to lose, I took the top off the carb to see if the float was not doing what floats do. Poured in some fuel and felt around. Boom! I found a very tiny piece of something like a pebble. Fished it out, put it all back together.

Primed it, started it and IT RUNS!!!!!

I took it around the block expecting it would shut off any moment. Made it back home with no problem.

My brother said that likely that pebble (or whatever it was) was jaming the float some how and causing it not to work.

I don't know if it is fixed for sure, but hey it's doing better than it did yesterDAY!!!

I have to say what a great forum and website FT Enthusiasts is. I would never have had any idea where to start to try to correct this carb issue. In fact, I have never posed a problem to this group and not gotten some helpful informatlion!

Thanks! Thanks! Thanks!!

Tony in New Mexico

 

Don't under estimate the power of a redneck brother in Fla.!!! Anyway glad your rolling again and KEEP ON TRUCKING!!!

 

Hi all,

Well, thought the problem was fixed. Got up to go the church this morning and let the truck run a but to warm up. Go less than a block and it died again. Came home after church and was going to push it back home. Decided to give it a try. It started and ran fine back home.

I suppose that there is some issue with the carb. Thansk for your help anyway. Wouldn't have gotten as far as I did without you!

Tony

 

I don't think you have a problem with the carb. If you've rebuilt it and have good gaskets, and sometimes it runs then maybe you have the problem I had. The bottom 8 nches of my gas tank had rusted real bad and my fuel filter was filling up with rust dust. And I'm not kidding when I say filling up. The truck had sat for 5 years and not only did the bottom of the tank rust but the brass float rotted away. The first time the truck died and would only run on primer gas I thought it was the fuel pump because the fuel bowl in the carb was dry. So I put in a new fuel pump and when I looked at the fuel filter, it was about 3/4 full of fine rust dust. I started the truck and got about 4-5 blocks from the house and it dies again. So I pull off the fuel filter and it's filled with dust again. Cleaned it out and it still won't run. So I remove the gas tank and it turns out that part of the brass float hadn't rotted away and was sitting right under the siphon tube at the bottom of the tank. So I don't even know if the rust was ever the problem or not but I do know the brass piece of the float was plugging the siphon tube. The fact that your truck runs great sometimes makes me think that your carb is OK but fuel isn't getting delivered. You can check this by removing the top. If the fuel bowl is empty then you're not getting fuel to the carb.

 

Are you running a vented cap or does your truck have the charcoal canister down on the right frame rail behind the radiator?
I bought a truck from a guy that was obviously chasing a fuel problem. He had replaced the carb, fuel filter and fuel pump. I bought the truck and as I was driving it home, it died a few miles away. I filled it up with gas and it ran. When it got down near half a tank, it died again. I thought the pick up tube in the tank had a hole in it about half-way up. To make a long story short, the problem was that the charcoal canister was plugged not allowing the tank to vent. When the pump couldn't suck anymore, the truck quit running.
There are two different tanks, vented (with evap canister and non-vented cap) and non-vented tank (without evap canister but using vented cap).
I went to a junkyard, got a tank that doesn't have the vent lines on the top for $20, took off the evap canister and bought a vented cap.
End of problem.

 

I haven't totally rebuilt the carb. Just put in a couple of gaskets that I thought sealed a gas leak. Am considering buying a rebuild kit though I have never done it before. May be easier to just get one from PEP boys and avoid the agravation.

Tony