VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Gas Tank connection-plugged fuel line

OK, it has been 2 years since my '29 ran well. I rebuilt the carb and she started up again, and ran like she used to. Two weeks later, she won't start again. Pump seems to work OK but there is no gas dripping out of the pipe from the tank. Shouldn't there be? I'm afraid if I take off the pipe from the tank, I'll get a face and garage for of gas. Is there a filter here?

Jim,
There is no factory filter only the screen at the fuel pump.

First thing to try is tapping on the fuel inlet to the carburetor with a screwdriver handle. It only takes a teensy bit of polymerized gas to glue the needle to the seat in the closed position. Tapping will generally break it free. If that does not work check the fuel pump.

If the pump is not providing gas to the carburetor. Take off the line at the inlet to fuel pump, put short section of hose on tube and blow back toward the gas tank. Is it easy or hard? hear (or someone at the tank with cap removed) air bubbles in the tank? If no bubbles then use higher air pressure to blow out the crud. Just remember if it plugged once it will surely plug again (often at the most inopportune time). Most likely you will need to clean the tank. Post again if that is the case. There are several options.

If line is clear then check the fuel pump. First make sure the glass bowl in tightly seated. Any air leaks on the suction side will result in no gas being pumped. If all that looks good then remove pump and operate it by hand. If you seal outlet with finger and pump do you build up pressure on your finger? If yes, do you get suction on inlet? If no then leak at bowl or inlet valve not working properly.

Once you get that far and still no gas post your findings and we will precede to step 3.

Thanks Chipper,

I'll get back to it in the morning. Too Hot today!

That blew open with little effort. And peering in the gas tank, it is quite rusty. i'm gonna put more gas in it tomorrow and give it another shot. More gas to mix the rust in better.

The rusty tank gives me pause. Is there an easy way to clean one out?

There are many comments on this site about cleaning and replacing gas tanks. Try a search with the following search criteria: +gas +tank +clean

That being said, something that I did with my old '27 truck is to place a strong magnet on the outside of the tank close to where the fuel line is. My theory is that rust will collect around the magnetic field and not go into the fuel line.

Kinda hokey, but an interim thing to try.

Cheers, Dean

If your gas tank is that rusty don't run the car. You are risking contaminating your fuel system (including the carburetor) even further.

once i blew into the tank to fuel pump line from the fuel pump it now is clear.
blew into the fuel pump to carb line and its clear.

rebuilt the fuel pump again. no contamination found.

checked the glass bowl conection, seems tight enough...

put it all back together and the glass bowl does not fill with gas.

is there another step?

Yes, i will search for tank clean as soon as i get this puppy running again.

The Fuel bowl will NOT just fill up, you have to pump fuel through the line. on mine i just spun the engine, hold starter pedal down like trying to start it for a few seconds, take a break, then a few more seconds, did this until fuel filled the bowl and then made its way to the carb.

Tips and details here: 1929 Fuel Filter, Screen, & Gasket Installation

If you are going to get another tank or have your existing tank boiled out, it is strongly suggested not to run the car until you do so.

I got the message JYD I'll start reading now on how to remove the tank.

Take the fuel pump off the engine. Operate the pump by hand. How far does the arm move before it meet resistance? If only a short distance then diaphragm, springs, arm are properly installed. If not then check assembly.

If you seal the outlet with a finger and pump it is there any pressure when you release your finger? If yes the pump and two valves are working okay. Now put finger on inlet and pump. When you pull off finger is there a vacuum? If not the bowl is most likely leaking. Are you using a cork or rubber bowl gasket? The bowl seat needs to be flat to use a rubber gasket. Prolonged pressure will warp the bowl seat and make sealing with rubber gasket impossible. I always use a thick cork as it will compensate for a little warp.

Take the fuel pump off the engine. Operate the pump by hand. How far does the arm move before it meet resistance? If only a short distance then diaphragm, springs, arm are properly installed. If not then check assembly.

Short Distance

If you seal the outlet with a finger and pump it is there any pressure when you release your finger? If yes the pump and two valves are working okay.

YES

Now put finger on inlet and pump. When you pull off finger is there a vacuum?

Yes, but its a very slight vacuum

If not the bowl is most likely leaking. Are you using a cork or rubber bowl gasket? The bowl seat needs to be flat to use a rubber gasket. Prolonged pressure will warp the bowl seat and make sealing with rubber gasket impossible. I always use a thick cork as it will compensate for a little warp.

Hmm. The was a recent rebuild kit, but I'll recheck both the bowl gasket and the diaphragm for leaks and fit.

Very slight vacuum at the inlet indicates an air leak. Particularly if the amount of vacuum is much less than pressure at outlet. Not likely a leak at the diaphragm but more likely at the glass bowl gasket. You can also try a drop of oil on each of the valves. I would suggest one at a time. If that dramatically increases the pressure and/or vacuum then the valves are leaking. May not be a big problem as gasoline on the valves helps seal them. Replacing valve wafers might help. Not easy to lap in the seats. A pencil eraser rotated around the seat will remove any crud and not groove the metal seat.

OK, all back together. Still have a leak problem. I found that if I remove the screen from the fuel pump, I get proper vacuum. With it in, I have leak.

So what is the correct order to assemble
washer, screen and glass bowl? or
screen, washer, and glass bowl?

Also, bought a paper filter from FS that fits in the bowl. Not original, but it seems it would give me further protection from and future rusting. Any comments about thisd?

Jim

The screen is installed in the fuel pump first, then the bowl gasket and finally the glass bowl.

There should be a ledge for the screen to fit into. I use cork gaskets as they seem to seal better than neoprene particularly if the surfaces are not smooth and flat.

not sure if this helps, but this is how I assembled it all on my 1929, i did use the paper filter

Thanks BearsFan315.

Now I have a question. You show a gasket on the fuel pump with the screen, and also a gasket installed on the glass along with the filter.

You don't have two rubber gaskets do you?

I use a non original solution taken from the boating outboard engine users.
Just buy an in-line hand rubber primer(at most boat stores). Insert in the fuel line before the fuel pump. To fill : fuel filter-fuel pump-carburetor, just squezze the primer several times until a hard resistance is felt. This means fuelling is complete and float chamber stops fuel in the carburetor to prevent from overflooding.
It is not "original" restoring, but saves a lot of battery cranking, specially after some long time since last car use.