fuel supply problem??

[bgalla]

This is about my 31 A. All stock, unmodified. It is in my metal building and not my driver right now. I do start it up and run it around the block every 4-6 weeks, just to keep things working. Even with this things varnish up and require removing the carburetor cleaning it etc.
This time after cleaning it (also a new needle valve) it starts right up runs fine for 5-10 seconds, then seems to run out of gas and dies. I let it sit for a minute or two and the same thing happens. Starts right up then dies in a short period of time. Removed the carb, cleaned it all well, needle valve works with a blow or suck upright and over. Good fuel free flow from the line. The float level has not changed. Puzzles me! Any suggestions? thanks Bruce

[Gary WA]

Originally Posted by bgalla

This is about my 31 A. All stock, unmodified. It is in my metal building and not my driver right now. I do start it up and run it around the block every 4-6 weeks, just to keep things working. Even with this things varnish up and require removing the carburetor cleaning it etc.
This time after cleaning it (also a new needle valve) it starts right up runs fine for 5-10 seconds, then seems to run out of gas and dies. I let it sit for a minute or two and the same thing happens. Starts right up then dies in a short period of time. Removed the carb, cleaned it all well, needle valve works with a blow or suck upright and over. Good fuel free flow from the line. The float level has not changed. Puzzles me! Any suggestions? thanks Bruce

Rust in the tank! Stopping fuel flow!

[Big hammer]

Gas shut off valve open ? It happens !

Or gas cap knot venting, remove the cap and try it

[Phil Brown]

fuel line pushed too far into the carb inlet blocking the flow

[Banditorama]

If its dying in under 10s, I doubt its a fuel supply issue. Mine will idle for over a minute with the gas valve shut off. But if you want to do a quick easy test: With the engine off, put something under the carb to catch fuel, remove the bowl drain plug, and turn the gas valve on. Should get a nice steady flow, if not either big hammer or Phil might be correct

[Joe K]

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The immediate solution for the "rust in the gas tank" option are the accessory "filter screens" which are installed in the "top" of the gas tank shutoff valve - and which you have to have the tank empty before removing the valve to install the filter - which you simply "push" into the hole in the valve. The filter is surrounded by the fuel in the tank and rust stoppage is unusual but not impossible after installation.

An augmented version of this somehow uses a vacuum cleaner or magnet to remove loose rust while the gasoline level is down and the interior can be seen.

The more permanent solution involves removing the tank, filling it with square nuts and possibly blasting grit, and then rotating or jiggling the tank extensively while partly full of kerosene. There are various coatings one can use to limit further corrosion - each with various downsides associated with them.

The ultimate solution are specialist who cut open the tank, remove rust electrolytically or otherwise, and weld the tank afterwards.

Joe K

[Rob Doe]

Check the main and cap jets for leaking at their bases. I had the same symptoms with a carb. I've got a long middle finger and could touch the two jets. They were dry at the top but wet at their bottoms. The gaskets were leaking. I got the black (plastic???) gaskets from Bratton's and the problem stopped.

I dropped the bottom half of the carb off and leveled it on the bench with wooden shims. Placed fuel in the fuel bowl and waited to see if the new gaskets leaked. They did not. The traditional red and gray did. Others have put a small amount of gasket sealer on the traditional ones to solve this type of leak.

[bgalla]

Thanks guys. I have taken off the filter to carb line and there is excellent flow out of the glass bowl filter. The suggestions made me realized I have not checked the carb screen filter which I will do. Also will remove the bowl drain plug and check the flow. Next the hammer. Bruce

[midgetracer]

using a vacuum cleaner to clean a gas tank is a sure way to burn down your car and the building it is in at the time. I am sure Joe K did not think that one through.

[rotorwrench]

All partial cleaning attempts are temporary at best.

[Gary WA]

Originally Posted by midgetracer

using a vacuum cleaner to clean a gas tank is a sure way to burn down your car and the building it is in at the time. I am sure Joe K did not think that one through.

Agree not a good Idea- Sparks and static electricity!!Boom!!!!

[JOES31]

Vacuum can be used.....On a dry tank. Wet tank...Boom!

[Brentwood Bob]

Throw some CO2 , or some dry ice in a dry tank if you are a gambler. Know a case of explosion by a lifetime builder that went south. Gas fumes linger. Best to not vacuum. Static electricity, or electric motor sparking will eventually materialize, IMHO.

[rackops]

I've had the same problem recently. My first reaction was "junk in the tank!" but after draining the tank and inspecting it, I found that the tank insides were beautiful. Checking my in-line filter on top of the gas shut off valve, there wasn't a speck of anything on the filter. I also took apart my cast iron bulb. Nothing. Clean and clean.

I went as far as removing and cleaning the spark plugs, replacing the (modern) points, replacing the distributor cam, removing and inspecting the intake and exhaust manifolds for leaks. Checked for compression (all good). Couldn't check for vacuum as the car wasn't running. I retimed the car at least a dozen times. Still, no smoking gun.

I've been testing rebuilt carburetors and went through three carbs on the car as well. Still, no fix. Finally, on the fourth carburetor, I was able to get it to run and took it on several nice drives on Saturday.

Keep in mind: two months ago, I had no issue driving the car 100+ miles on weekends. It's a solid driver and I take great care of the engine, mechanically and cosmetically.

Interestingly enough, after cleaning and reinstalling the previous carburetors, I haven't had a significant issue since.

What was the issue? I honestly don't know. For as simple of a system as the Model A, there are a lot of things that have to be "just right" in order for it to work properly. I'm assuming it was something I did in one of the steps I performed that was the "right" thing...but what exactly it was, I don't know.