Truck is not getting fuel

[popsthebuilder]

Drove truck to mechanic for a general inspection. Asked them to make sure that both tanks were in working order. Mechanic said everything was ok. Left mechanic and truck started acting as if it was out of gas. PO said he put $25 in each tank prior to shipment. Havent' driven 20 miles. So I barely make it to the gas station. I attemp to put gas in right tank and gas sprays out as if it is completely full, or blocked off somehow. Push truck to other side of pump. I am able to put almost $30 worth in left tank. Truck starts back up after depressing petal a little. Back on the road. Drive maybe 10 miles. Truck sputters and dies as if out of gas when I come to a stop, and there it sets. What the heck? I'm ging to take a section of hose with me when I go get the truck to siphon gas and be sure that both tanks are nearly full. I read a few threads that were related. Usually, what is the cause for this behavior? Thanks for any help, really.

[bd]

Assuming the '73 (in order)...

Check your tank selector to make sure it's switching.

Replace the fuel filter.

Check the fuel pump suction (20+" Hg), pressure (5-7 PSI), and delivery volume (1+ qt in 20 seconds of cranking).

[DnStClr]

Your mechanic owes you some money.

[bake74]

Replace the fuel filter.

     Sounds like a classic case of dirty filter.  As gas flows forward the filter continues to plug until not enough gas to keep your truck running.  Let it sit, the particulates in the filter settle to bottom of filter, start it up and runs again for the next 10 miles and happens again.  Been there, done that on many different types of engines.

Your mechanic owes you some money.

     Yea, at the least he should have checked the fuel filter if you took it in to check both gas tanks for operation.

[popsthebuilder]

After messing around with the tanks, lines, pump, and filter I found the main problem. It was a really simple fix that I completely over looked. When I got back to the truck I used a large section of hose inserted in tanks to confirm that gas was indeed in both tanks. Aux. tank is slap full. Main tank still had gas in filler neck from attempting to put gas in earlier so I figured both were full and started inspecting other fuel system components for the problem. Switch and valve have been completely bypassed. I ended up replacing the pump after removing hoses, filters and so forth trying to find a clog. The whole problem was due to a somewhat kinked filler neck on main tank. Yes I am a moron. Anyway, couple or questions.
1)After unscrewing the fuel line at the carb/ filter I cannot get a good seal and have a small leak. I found what looks like some sort of gasket at this connection. Does this gasket come with a new filter? If not can I use teflon tape, or will gas eat that stuff up? What type of thread locker/ rubber gasket could I use here? Would it be better to try and find a replacement fitting going from line to carb?

2)Auxiliary tank is full of gas. Want to install manual valve to switch tanks under truck if and when needed. What type of valve would I need, made of what material? 

[454Man]

I use Teflon tape on mine

[bake74]

     I believe that the carb filter comes with a small "crush washer" gasket with the filter you are suppose to use.

[bd]

After unscrewing the fuel line at the carb/ filter I cannot get a good seal and have a small leak. I found what looks like some sort of gasket at this connection. Does this gasket come with a new filter? If not can I use teflon tape, or will gas eat that stuff up? What type of thread locker/ rubber gasket could I use here? Would it be better to try and find a replacement fitting going from line to carb?

The carb inlet nut that retains the fuel filter is sealed with a nylon gasket that snaps onto the end of the nut.  The gasket adhering to the fuel filter itself won't cause an external leak. 

Slip a new nylon gasket onto the inlet nut and thread the nut into the carburetor.  Wrap two turns of Teflon tape around the threads of the fuel line nut and tighten with a 5/8" 6-point flare wrench while backing up the inlet nut with a 1" open end.  The Teflon tape doesn't actually seal the threads, but acts like a dry lubricant so the fuel line nut can be sufficiently torqued to seat the flare.

[popsthebuilder]

I made a sort of mechanical selector valve for truck to drain gas from auxiliary tank that was put in a tank that looks like it has been bypassed for years. The valve system is made up of two separate 1/4 turn brass 1/4" ball valves designed for 50-200psi air, a tee, and some ntp fittings w/ repair style ends for 1/4" flexible hose. Used 1/4" fuel line from valves to preexisting splices either rigid or hose. Strapped and screwed up. Drove about 30 miles on aux., then filled main tank and switched to it. Everything seams to be working fine for now, but...
1)was gas affect the inner workings of the valves which are designed for air?

Night before last in a frenzy to repair nonexistent fuel problem my brother in law cross threaded the fuel inlet going to carb, causing pretty serious leak. (Still leaked w/ nylon gasket) Today I chose to us a matching size o-ring that fit into gas inlet and a large amount of teflon tape. After a couple of tries I managed to thread straight and stop leak.
2)Will the gas eat up a standard o-ring and, or teflon tape? I keep getting mixed answers.
     Also hear a light popping from exhaust, more on one side than the other. There is no cat back. Is it missing or detonating? Could this be a timing advance/ retard issue (Maybe the distributor cap is loose.)   

[bd]

...Night before last in a frenzy to repair nonexistent fuel problem my brother in law cross threaded the fuel inlet going to carb, causing pretty serious leak. (Still leaked w/ nylon gasket) Today I chose to us a matching size o-ring that fit into gas inlet and a large amount of teflon tape. After a couple of tries I managed to thread straight and stop leak.

Will the gas eat up a standard o-ring and, or teflon tape? I keep getting mixed answers.
Also hear a light popping from exhaust, more on one side than the other. There is no cat back. Is it missing or detonating? Could this be a timing advance/ retard issue (Maybe the distributor cap is loose.)

Next time you have to remove the inlet nut to replace the fuel filter, replace the inlet nut too, with an oversize, self-tapping nut that is specifically made to repair stripped carburetor threads.  They should be available at most auto parts stores.

Teflon tape is impervious to automotive pump gas.  However, the o-ring may eventually fail unless it's made of Viton, because of the alcohol added to gasoline.

Popping out the exhaust at idle is more likely from fuel that's not fully combusted, entering the exhaust.  Try adjusting the idle mixture screws (leaner); make sure they are balanced in their adjustment (the same number of turns out from seated).  Check the timing (retarded timing also can cause popping).

The 'air fittings' will probably survive, as long as they don't contain any rubber seals.  Check them periodically.  Eventually, you might consider installing an electric tank selector valve and switch.

[popsthebuilder]

Thanks for the advice bd. Sounds right on. Had no clue about the over sized inlet. Priced new stock rebuild carb (hd rochester) price is around $260 core $50. My existing is only working on two barrels, and most vac. lines are missing. should I attemp to repair or just replace?

[mehunter1]

hey man I would check with National Carburetors (http://www.nationalcarburetors.com/) I got one from them and it is field tested right there in the shop.  It bolted right on with no adjustments and truck fired right up.  I would definitely recommend them for a replacement q-jet.