i also have a question concerning the fuel screen. i have been taking these tanks out for 30 years on 7 different trucks all slicks and have never seen the screen when i looked in there to clean them. my question is how are they replaced as the suction tube is a welded in piece of pipe. i have two tanks in storage. gonna go look at them and see if i can spot the screen. dutch

 

Tedster9,

I have the tank out of my '61 F-100 right now and I think your '64 is the same tank. The pickup tube fitting is permanently affixed to the tank. (my '68 is the same.) In later models, I think they moved the tube & fitting to the sender mounting plate, but I do not know if the dimensions of the sender mounts are compatible. Maybe Bill can tell us if they used the same five-screw gasket through all the models. As I remember I saw the tube-in-sender on an '80.

I think it would be possible to abandon the original hole - inverted flare plugs are available at most parts stores, so you could seal it up properly. If the later sending units will not fit directly, it might be possible to modify your sender mounting plate to accept a new pickup tube.

Flyn66dtmn, I agree with Bill - the mesh screen slides onto the tube. This is easy to handle if the pickup tube comes out with the sender, but I do not know how you would replace one that is on a tube permanently installed in the tank.

 

I tired to modify the sending unit to add a pickup to it. There isn't enough room in my opinion. I ended up using a length of -6 stainless steel tubing with AN fittings and a 90 degree elbow mounted between the sending unit hole and original pickup. It was a slight challange to tighten down the b-nut but I did manage to get it on with the use of mechanics wire to hold the tube and b-nut in place long enough to start the threads. Then tighten it all down with a wrench. To get the depth your going to need use a wire coat hanger to measure then figure in the rest of the parts to get it just right. If I remember right the bottom of my new tube is some where between 1/4 and 3/8 off the bottom of the tank.

 

There are two different gaskets. One is thick cork (C1TF-9276-A) with the 6 holes. The other is the "O"-ring neoprene type (C0AZ-9276-A). One will not work in place of the other. The "O"-ring type was used after 1966.

 

Dontcha think it's time for a break?

Seriously I don't know what to think - maybe the screen is long plugged, and the tube corroded, since adding 5 gallons and it will start right up once the carb is filled again. It means only about half the tank is usable at this point, or at least I'm not gonna try and experiment on the highway!

Anyone wanna comment on the mileage? What is typical for a 292 F100 anyway?

I'd also be interested where any high resistance points would be in the fuel gage circuit, as I tried a new sending unit, float, and constant voltage regulator, but the gage will never read more than 3/4 full yet pegs when grounded to frame.

 

In several different 292-powered passenger cars, with less wind resistance than a pickup, I have gotten between 16 & 18 mpg on the highway, cruising at 55, with overdrive. Under the same conditions, I would think a pickup could do between 14 & 16.

Your tank sender is likely to be the problem, so long as the wiring is all hooked up, including the ground at the tank. All this wiring is inside, so it is not exposed to the weather. In my '68, the gage either goes from empty to 1/2-full, or does not bother to move off of E. Senders do wear out. Ground problems in the dash can make all electrical gages all act "funny" - I usually notice it in the temperature gage first.

Back to trying to help you with your original question. The in-cab tank is on about the same level with the carb. When it is full, the fuel pump does not have to work very hard at all. It could be that you have a weak pump. I recommend you do a pressure test to see how much pressure the pump makes. There is also a volume test, but I suspect your problem could be pressure-related. This would be a lot easier to fix than the tank-tube problem.

P.S.: Back to the filter on the tube. I wonder if the sealer is clogging up your pickup screen. It would be hard to put a new one on, but I would try (gently) blowing back into the tank with the filler cap off. You should be able to make bubbles that you will be able to hear. If there is a lot of resistance, the screen may have been "sealed" along with the tank. I think that it might be possible, with the tank removed and empty, to use air pressure to blow the filter off the tube. Putting a new one on would be almost impossible, but you could run with a large in-line filter to keep garbage out of the pump and carb.

 

I can understand not wanting to experiment on the highway. However I would try blowing back threw the pickup tube when it does stall to see if you are collecting a bunch of junk on the end of it. I had to do that a lot after I drained and cleaned out the tank and installed the new tube. Crap was still falling off the sides large enough stop the flow, even on the side of the highway a few times. I still carry a 12" piece of rubber hose in case it happens again. So far it's been 3 years since the last time I had to do it. On a side note, don't they sell the huge gas cans at truck stops?

To be honest I couldn't tell you what the milage would be for a 292. Never had one in my truck when I bought it.

I have the same guage problem though. I am thinking that the next time I have my dash apart I am going to monkey with the needle itself. I am pretty sure the needle is pressed on the spring inside the guage. When I am close to empty physically the guage is showing below E. That is why I want to monkey with it.

 

This probably isnt your problem, but I figured I'd throw it out anyway. I had a problem on a 65 F-350 where I had it running for a little while but it ran worse and worse (Read: random chance for it to actually start) Until it started no more. I ended up pulling the tank and it was filthy inside. I'm assuming your tank is not that bad, but if a piece of rust ect, that is just wide enough to block the bottom of the pickup tube, it will stop everything. So even if its running now, there is a slight chance that the tube will suck the piece of rust up again, blocking fuel flow. Again, if its big enough it wont actually go into the pickup tube but just block it. Just a thought and good luck.
Garrett

 

Just to lighten things up: I trouble-shot a neighbor's tractor which would run good & bad. Everything else it could have been checked out, so I told him there was a good chance that (as Garrett's suggests), something in the tank was floating in to block fuel pickup and then floating away. The next time my neighbor saw me he was a happy man - problem solved. He had fished a small snake out of his tank!

 

I didn't mention one other thing because the OP had changed his fuel pump.

Ford had fuel filters mounted to the fuel pumps on some 6 and V8 engines from the late 1950's thru the 1970's. If your fuel filter has a approx. 6" can with serrated edges either mounted to the top or bottom of the pump, there's a fuel filter inside it. Most ppl have no idea it's there, so it rarely gets changed. The can unscrews, but be careful doing this, it may be stuck on.


C4AZ-9365-A .. Fuel Filter (Motorcraft FG-1)

 

I did forget about the pump being "fairly new", but I would test it all the same. Even new parts can have defects. More than once I was told that a component "could not be the problem" because it had already been replaced, but, the new part turned out to be a bad part.

 

It's got maybe 10,000 miles on the pump. Not exactly a high quality aftermarket job, but.

And they are cheap enough, I could try a new one no problem. This all started once I got it running well. Hm. The thing to do is remedy the problem from the tank - there's no way to tell, but the fuel pump could be clogged too - the canister filter that is.

Hell, is there an easy conversion to add another tank between the rails? I'd drop the coin just to have increased range. I'd still need to get the original tank repaired because I'm guessing the extra fuel needs to be pumped to the in-cab tank?

 

15 would be OK. I replaced the tank sending unit, with exactly zero change in
gage calibration. The temperature gage doesn't do a hell of a lot, either, it indicates a very low temp. Tried cleaning all the connections in the dash cluster, and the dash voltage regulator. What "ground problems" am I looking for?

 

The whole gage assembly that you can remove needs to get a ground for all the gages. If "thumping" on the dash (or a rough road) makes the gages act funny, this could be the problem. My '68's gages would occasionally do funny things when the clutch linkage was moved, causing some part of the ground path to be interrupted. You can connect a jumper wire from the gage assembly to a known good ground - the firewall, for example. Sometimes just taking the gage assembly out and putting it back in will "fix" the ground problem.

P.S.: The most common way to add a second tank in our pickups is to use a two-way manual valve that mounts on the floor between the seat and the door. One position is for the original tank and the other is for the additional tank. The fuel line already runs right by this location, so you can easily plumb it in with fuel hose and hose clamps. There are a number of threads discussing the possibilites for places to install tanks and sources to acquire them from. It is easy to switch the valve from one tank to the other. Some people use an electrical solenoid valve to do the same thing, which is even easier.

 

That story reminds me of two others. There is one guy who used to milk cows around us and he told me that he was mowing hay one day and the tractor just shut off and he couldnt get it started again. He drained the fuel and inside there was a big beetle that was blocking the fuel line. Also, my boss's tractor's fuel bowl got water in it and it froze and broke off the line. It was during the winter and he didnt need it then anyway. When he fixed it a month or so ago, It wasnt getting fuel. He took it apart and some sort of insect had built a nest in the line between the bowl and injecter pump! Its amazing what problems can arise in fuel systems, some more bizarre than others!