If the hoses have not been replaced recently replace ALL of the rubber hose. A friend of mine had a truck for a few weeks before one leaked and the resulting fire destroyed his truck.

 

Where should the rubber hose go once it leaves the fuel bowl vent valve port on the 2150 air horn? Any pictures? Thanks in advance!

 

Is it shown here?

http://mil1ion.clubfte.com/FordVacuumDiagrams.html

 

Thanks for the diagram, however it doesn't show where the line should run. The line I am referring to attaches to the air horn, directly above the fuel bowl and serves as a vent to the fuel bowl. I have nothing attached to this vent port. I only learned of it by reading "Bubba's M-Block Ford V8 Workshop" website:


The diagram above illustrates it as #3. Could you assist me with this?

Thanks, as always!

 

I'm pretty sure the fuel bowl vent routes into the charcoal cannister, along with the fuel tank vent.

 

those usually run to a charcoal canister that runs back to the gas tank....EDIT:dang, he beat me to it!!

 

Thanks, guys! I'll take a look at that. The p.o. removed a lot of those lines, but at least left the components in place. I'm having a fuel delivery problem and wonder if this vent is plugged up. If it were to be stopped up, would it effect the fuel being delivered to the fuel bowl?

 

No, it only vents the fuel vapors to the charcoal canister to keep them from being admitted into the air. The most common fuel delivery problem on these old trucks is a dry rotted rubber line from the tank to the frame which allows air to be sucked in.

 

Well...I changed all of my rubber lines between the tank and the fuel pump. I even went a step further and dropped the fuel tank so I could clean it out and take a look at the suction tube inside. I found that the hard plastic piece on the end of the suction tube was broke in half, and the other half was rolling around in there. Naturally, there was no filter on this piece...either removed by PO or disinigrated over time. I removed both halves of the plastic piece and replaced it with a short stainless steel tube to make sure I am able to get all of that high dollar gas out of there while driving. I coupled it onto the suction tube/sending unit assembly by using a 1" piece of rubber fuel line. I'm not sure if that was a good idea or not----submersing fuel line into gas. Hope it lasts a long time. By the way, since I no longer have a sock in the tank, I installed a steel fuel filter in the line that leaves the tank and connects to the steel fuel line on the frame.
After the tank was remounted and filled up, I cranked it and noticed that the clear fuel filter I installed up near the dizzy showed the same symptoms as before I did all of this work. The filter won't fill up. Again, by that I mean that it looks virtually empty. Sometimes while it's running, it will reach half way full, but it will eventually all get pumped out into the carb. I don't understand why it won't stay at least half full all the time. I guess I shouldn't worry about it, as long as it keeps running. Any opinions out there?....

 

Just a thought, how does it run? Is it smooth at idle and at speed? I was wondering if the needle in the carb could have dirt in it? This might let air in and allow the gas to drain back into the tank. I do not know if this is possible but might be worth a look. Erv

 

The engine idles great and runs fine down the road. I can't figure out what the deal is. Are you talking about the needle valve that is connected to the float? While the truck is running, the float should be continually dropping slightly and letting fuel into the bowl.

 

A filter should not be used on the suction side or inlet side of the pump.

 

I noticed the same problem with my '71, returned the lifetime pump to A-Z (10 yrs old-wow) for replacement and had same result. More intensified research (aka reading) revealed the pump would allow fuel to drain back as an emission feature. Comparison of the motorcraft and holley (miss that Holley) carbs revealed that once the needle valve opens on the motorcraft, fuel can drain out of the bowl. Past that it's just a hot start issue, with less fuel draining down the manifold. I'll probably be replacing starters more often.

 

I've had the same fuel filter trouble on my '75 4wd, as far as your lack of fuel problem you may want to check the clearance between your fuel lines and exhaust manifold ( see how hot it's getting), you may be experiencing a vapor lock issue, remember that gas boils much sooner than water. Keep us posted on what you find!

 

Actually, that was a theory that I had after reading MANY threads on FTE. I found that the steel line that runs along the inside of the frame rail was not fastened with the stock clips and allowed the line to lean over and get very close to the manifold...less than 1" away. I properly secured the line using the clips that the PO over just overlooked and that kept it about 6-8" away. Unfortunately, this action did not change the symptoms of the fuel filter that I described earlier. Thanks for the 2 cents worth. If you have more suggestions, feel free to share.