Starving for gas at highway speed

[Chris Haynes]

Today is the first time I took my car onto the highway. Runs great but it is starving for gas at highway speed. Gas filter is clean. New fuel line. What should I look at?

[Railcarmover]

pull your strainer and look in your fuel tank

[fordcragar]

I was thinking fuel pump, but forgot most Model A's are gravity feed.

[Charlie Stephens]

Check to be sure the vent in your gas cap isn't partially blocked.

Charlie Stephens

[H. L. Chauvin]

Hi Chris,

Per your post: "Starving at highway speed. Gas filter is clean. What should I look at?"

1. First, what kind of gas filter? If you have an in-line gas filter, many in-line fuel filters are designed to be used in vehicles with pressurized fuel pumps and many said in-line filters do not allow enough constant fuel flow with the Model A non-pressurized gravity flow of fuel.

2. Second, have no idea how clean is your fuel tank; however, even if it is immaculate, if you ever fill up at a pump in the future that has poor fuel filtration, you will wish you had installed a Cylindrical Vertical Gas Tank Screen, Model A Part No. A9193-T 1928-31 like those from Model A parts suppliers. Please install one if one is not installed to help prevent "any" type of fuel blockage between the fuel tank and the intake manifold.

3. Maybe try opening your carburetor's GAV when starving for fuel and let us know what happens .... could also be a leaking intake manifold providing more air and not enough fuel.

[Mike V. Florida]

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What exactly do you mean "starving for fuel"? What is the car doing?

[Patrick L.]

All good info, especially about the gas cap vent [ open gas cap and drive it].

Also make sure the new fuel line isn't pushed too far into the carburetor. End of line should be about 1/16" from end of ferrule.

I use an in-line filter with no issues.

[steve s]

Remove the filter--at least give it a try.

[Dick Steinkamp]

Remove the fuel line from the carb with a pan under it to catch the gas. If you have a nice steady flow of gas, the problem is in the carb. If not, the problem is a restriction somewhere from the tank to the carb.

[Kurt in NJ]

On my car I found the pencil filter in the tank was the fuel flow problem---i removed it and flushed the tank several times ---after a 1000+ mile trip I no longer collected debris in the sediment bowl

I did look at the ends of the bowl to carb line, what the tubing was cut a dull cutter must have been used, the end was 1/2 closed off----like the tip of a hamster water bottle ----after both those things I could get a strong full diameter of the pipe constant flow

[Jacksonlll]

The dredded new fuel line. Hapens all the time. I bet Patrick is right. Just give the end a little circumcision. Let us know.

[clo2jim]

A few years ago with my 1930 Roadster I was having some issues running at highway speed and acceleration where the car was cutting out, like I had problems with fuel starvation. Once I got the car warmed up after startup and running well, I usually ran with the spark lever fully down. One day while I was experiencing the engine cutting out, I moved the spark level up a few notches and it smooth right out with no cutting out.

So could your issue be too more spark advance?

[henry's 31]

Chris:

All the solutions given should solve the problem. Make sure the in line filter you placed is a free flowing filter (not dependent on fuel pump). A good example is the ones used on Lawn mores. I use a John Deere filter available on the box stores #GY20709. Can you let us know what fixed the problem?

[western77]

90% of fuel problems are electrical. Check your gas cap vent! JB

[Chris Haynes]

Originally Posted by Mike V. Florida

What exactly do you mean "starving for fuel"? What is the car doing?

The carburetor runs out of gas. I back off the throttle a bit and the gas flow will then keep up with the demand.

[Chris Haynes]

Originally Posted by H. L. Chauvin

Hi Chris,

Per your post: "Starving at highway speed. Gas filter is clean. What should I look at?"

1. First, what kind of gas filter? If you have an in-line gas filter, many in-line fuel filters are designed to be used in vehicles with pressurized fuel pumps and many said in-line filters do not allow enough constant fuel flow with the Model A non-pressurized gravity flow of fuel.

I have the stock screen and bowl filter.

2. Second, have no idea how clean is your fuel tank; however, even if it is immaculate, if you ever fill up at a pump in the future that has poor fuel filtration, you will wish you had installed a Cylindrical Vertical Gas Tank Screen, Model A Part No. A9193-T 1928-31 like those from Model A parts suppliers. Please install one if one is not installed to help prevent "any" type of fuel blockage between the fuel tank and the intake manifold.

Mine is installed.

3. Maybe try opening your carburetor's GAV when starving for fuel and let us know what happens .... could also be a leaking intake manifold providing more air and not enough fuel.

That worsens the problem.

[Chris Haynes]

Originally Posted by Charlie Stephens

Check to be sure the vent in your gas cap isn't partially blocked.

Charlie Stephens

I'll remove the cap and see if that helps.

[H. L. Chauvin]

Hi Chris,

Usually while driving, after further opening the carburetor GAV makes one's Highway Speed engine sputtering worse, this is many times a sign that your air/fuel mixture is already too rich with fuel when the GAV is completely closed, and/or when the GAV is only 1/4 turn open.

In your statement, ("Today is the first time I took my car onto the highway."), does this mean that this is the first time that this carburetor has been tested on the highway; e.g., this carburetor was never observed by you where it formerly functioned properly.

Brief history of this carburetor may help to try to diagnose a possible carburetor problem.

[J Franklin]

Keep an eye on this thread also for more info on carb problems.

https://www.fordbarn.com/forum/showthread.php?t=223907

[P.S.]

Chris: Is the car at your Pine Grove home? If so, make the trip down the hill and bring it by my shop and we'll fix it.