It would be Dangerous to remove/replace the stand pipe because of gasoline vapors. Not sure, but thinking the pipe and it's female seat are likely Silver Soldered in place, I don't recall anything like a visible welding bead in it's attachment. Of course it can be safely done, if has to be. This after all is a FYI follow up and hopefully no need to deal with.

I have also found pin holes in the steel fuel line that runs along the frame from under cab to the flex hose at the fuel pump. A fuel pump/vacuum test gauge (Very Cheap Test Tool from auto parts store) hooked to the line under the cab, crank the engine over and the fuel pump should pull the gauge to 4 to 6 inches and hold when you stop cranking. Be Sure to disconnect the pump outlet because if the carb bowl is full, it won't allow the pump to pump. If it doesn't hold, attach the gauge to the fuel pump inlet and crank engine again and see if the reading holds, if YES then look to steel gas line as a/the problem.

I probably have to many FYI's. On a routine test of a fuel pump, always test, BOTH the inlet vacuum and outlet pressure (both lines disconnected) and that they Hold. If not holding, either a check valve is bad or debris is lodged in or under the valve seat. On an old style rebuild-able pump you could disassemble and check it out. On our Era trucks we mostly had the built in canister fuel filter. No built in filter, I like to see/ place one before the pump.

Cap

 

I once sealed a pickup tube by brushing some tank sealing compound on the outside, but that was a removable tube, not like our trucks. Any fuel resistant paint will work, but you would need to fabricate a reach around brush, and paint what you can't see.
With a section of clear hose, you could check the tube under light vacuum, just enough to lift the fuel part way and see if it holds or drops. Watch for bubbles.

 

Cap & Old: Thanks for the info. If it comes to what the two of you are talking about,
I'll just get a new tank and put it in. Also, I could drive the vehicle from the two auxiliary
tanks. That would be without the fuel gauge readout. I don't want to do that. I wanted
to start and run the truck off of the main tank and transition into the auxiliary tanks.
That way if I have an issue with either of them, I can still drive off of the main tank.
I check yesterday and I think I might have some blockage in the tank. I'm getting very
light flow out of the tank. Something like about half of the tube instead of a full tube.
The flow is so little that it won't carry all the way to the front by the pump.
I will recheck this issue today. I had blown air backwards into the tank when I first
started all of this and had air going into the tank. BUT, debris could simply float back
into the pickup. I'll look at it today.

 

as alway cap and oldie have been leading you 100% in the correct directions. sounds like you have a clogged line somewhere, since you have spark what's left is lack of gas, try taking a beer bottle cap full of gas drop it down the throat of the carb and try starting it, if it fires right off,you know for sure it's a gas feed issue,

in your post above you state 2017 to 2023 that's a lot of time for today's ethanol gas, which starts to break down in 30 days, starts to absorb water vapor from the air, that rootbeer color you saw was bad gas ,

 

I am away from my trucks right now, but going on memory, I don't believe the in cab tanks have a filter (sock) in the tank, as such, they can ingest debris and clog. It may just need a thorough flush and cleanup, best way is with tank removed so you can shake it around, Replace it if you prefer, but I think all it needs is a cleaning,

 

Captchas: Monday I plan on by passing the fuel tank and hook up a fuel cell directly in front of the
intake on the fuel pump. If that fires things up, then I'll pull the tank and clean out all the lines
again. I knew the root beer was bad gas. The main tank looked ok. I had asked the seller what gas
they had been using and they replied "Just regular gas". That was in Florida and I don't know if
they are an ethanol state or not. It fired right up and ran well when I tested it.

Oldie: If I pull the tank, which is probably what I'll do, is new gas the acceptable form of fluid to
clean the tank? Otherwise what else would be?
I'll also check the pickup tube for corrosion and whatnot.
I know the 67 original did not have a sock filter on the pickup tube.
I would prefer to keep the old tank only because it is period correct and painted the same color as
the truck. Not the greatest reason, but it is mine.

Mike

 

I live in Fl and unless you specifically find and buy Non-ethanol you are getting minimum 10 % ethanol in regular gas.
You could disconnect and clean out the seat tank seal it off and leave for the appearance and run off the auxiliary tank. That would get the fuel vapors/smell out of the cab
I removed mine for the extra room and smell, but I wasn’t concerned with original appearance

 

Regular gas will work for light flushing, it depends how much you want to do, use a magnet to get the rust chunks out first. Por 15, among others, have a product for cleaning tanks, usually used with their sealer, which is what I would do. Or, if you can still find an old school rad shop, they can flush and seal it.
Your pickup tube is likely fine, but it will end up getting sealed anyway if you seal the tank, you just slosh the sealer around and it coats everything inside, so remove the sender and tape the hole. The clear hose test I detailed earlier is how we check for air leaks with a diesel, nothing is more frustrating than a diesel sucking air!

 

Sometimes I'm not thinking straight. I just remembered that I recently bought a borescope
specifically so that I can see into "hidden" spots. Monday, I'll drain the tank and have a
look/see at the condition of the tank. I'll also magnet the areas I can reach with a telescoping
magnet. If all of that fails it's time to pull the tank.
I've got a gas station that is about 10-15 miles from me that has non-ethanol gas. That's where
I've been getting my gas for the 67 as well as my 41.

Mike

 

that 67 has a fine mesh sock on the pickup. been that way for years before that truck was made , for a note i just had a running issue with my 64 vette, no fuel to the pump, issue was the sock on the pickup, and that one is NO JOY to replace.

 

Cap. I have been informed that the thru 1967 there was no sock. Starting in 68 it might
or might not have a sock. Car versus truck was also different.
At any rate, I pull the tank this week and borescopes it as best I can. There was no sock
and the fill tube ended about 1/2" from the bottom of the tank. A helper and I sloshed
around new gas and then dumped it out. A bunch of gravelly junk came out. We did it again
and a very little came out. I re-borescoped it and it looked a bunch cleaner. There was still
some junk, but nothing that would block the pick-up tube. The only way to really get
everything out would be to put a small chain in it and rattle it around. I didn't think that
was necessary. The tank is back in the truck and ready for a test. Monday, I'll start with a
test jar of gas up by the fuel pump. If that works out well, I have blown out all the fuel lines
and will test the tank. Hopefully all goes well.

Mike

 

All sounds good. On trying to clean a tank with any accumulation on the bottom whether lawn mower to a vehicle, I will use nuts and bolts or maybe some 3/8 - 1/2 crushed stone dry and rinse with water, all easy to get out. You way is fine so long as you get the debris n junk out. Just like to add, any problem requires a process of elimination to the cause and that is what your in the midst of.

On "captchas" comment on sock at suction pipe. Don't recall on this era Ford Trucks. I think GM may have used them 1st. I stand corrected if need be.

Cap

 

think you right cap. gm first as i know my 57 belair had one on the pickup, don't know if it was OEM or not, my vette OMG was that a PITA, would have been easier to pull the tank, yet if i had to to or have to . next time, hello tanks and snipper efi .

good luck mike, seems to me your heading in the right direction