Starving for gas at highway speed

[jpcouture]

Make sure your float valve is not sticking or partially open. On a trip my A was stalling out over 30 MPH. We looked at everything on the road, including checking gas coming into the carb. I later found that my neoprene needle and seat was partially disolved due to Minnesota alcohol gas. There was gas coming in, but a dribble not a full stream. I now have an NOS needle and seat, best 12.00 I have spent on that car.

[Dick Steinkamp]

Originally Posted by Chris Haynes

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

To follow up on Mike's question...

What is the actual SYMPTOM (not your guess at the cause)? Be as specific as possible. Did it just start happening and run well a week ago? Did you change anything or do anything (even as simple as filled with fuel) just before it started happening? Does it always happen at a certain speed? Certain RPM in any gear? Can you make it miss just bringing up the RPM with the car at a stand still? What test have you performed that shows the carb float bowl empty when it starts running badly?

This could be a fuel flow problem or a carb problem, but a high speed miss could also be just about any other factor that can effect drivability (coil, condenser, point gap, timing, intermittent electrical short, bad ignition switch, valve clearance, dirty spark plugs, plug gap incorrect, vacuum leak, etc)

It's tough to diagnose a drivability problem over the internet, but more info might help. It's also tough (or counterproductive) to start implementing "solutions" before the cause is known.

[Chris Haynes]

Originally Posted by 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?

The only filter is the stock Ford unit on the firewall.

[Chris Haynes]

Originally Posted by 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.

H. L.,
I have no history on the carburetor. I recently purchased this non running car. I got it running and I'm working the bugs out of it. I had the head off and was pleasantly surprised surprised to find clean chambers with new pistons and valves. The light carbon wiped off with a squirt of Kroil and a rag.
Evidently a previous owner of the car didn't have much mechanical ability. I do know this car changed hands a few times during the last 12 months. In addition to not running the juice brakes were inoperative. Loose wires everywhere.
The warped exhaust manifold had blown a gasket. I R&R'ed the manifold and put the gland rings in the number 1 and 4 port with a new gasket and all is well now. A new manifold is on the way.
Speaking of the fuel line it was leaking at the strainer on the firewall. Inspection found the ferrule was barely on the end of the line. I pushed it on the new line far enough in to seal properly and that problem was solved.
The reason for the dry hydraulic system was a cross threaded "T" on the rear axle.
It had been converted to modern points with the Nu-Rex assembly. The plate adapter was grounding out on the distributor body. A little tweak and some shrink tube fixed that.
I am enjoying this car and I am having fun finding and exterminating its many bugs.
You should buy stock in Snyder's as this car is making them rich.

[Bruce Adams]

ALL OF THE ABOVE are right on the mark.
Just for kicks, use a tire pump with a pointed nozzle (Harbor Freight) and stick it in the fuel line, cap off, and gurgle some air into the tank to clear any of the usual suspects out of the way.
The "too long" fuel line would be my first check, though. Call a MOIL to help out.

[Chris Haynes]

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Originally Posted by Bruce Adams

Call a MOIL to help out.

I have no idea what a MOIL is.

[H. L. Chauvin]

Hi Chris,

This one (1) most wonderful statement:

"I am enjoying this car and I am having fun finding and exterminating its many bugs."

is a Revelation in itself that your Model A "will" no doubt run great, "Come Hell or High Water!"

Never a bad idea to try to obtain a spare carburetor to overhaul while you keep your Model A running at maybe a little less than highway speed ...... for example, this way, you don not have to remove your existing carburetor and experience the agony of "Model A Down-Time".

I'm be calling Snyder's on July the 5th to inquire about their stock quotes ... thanks for the tip.

[Chris Haynes]

I started tearing apart the fuel system to check things today. The first step was to drain the tank. I disconnected the fuel line from the carb. and stuck it in a container to drain the fuel. While it was draining something in the glass strainer bowl caught my eye. There was about 3/8" of water floating on top of the bowl. I am sure this was slowing down flow through the screen. Road test will tell.

[wmws]

That could be the problem. Won't run very well on water. Check out all the other good tips to be sure all is in order.

[JBill]

What do you consider "highway speed"? Highway speed around here is seventy to eighty mph.

[Dick Steinkamp]

Originally Posted by Chris Haynes

There was about 3/8" of water floating on top of the bowl. I am sure this was slowing down flow through the screen. Road test will tell.

???

Gas floats on water. Not visa versa.

It's good you drained the tank and got the water out. Continue checking for water in the float bowl. It will be on the bottom of the bowl if there still is some.

[Chris Haynes]

Originally Posted by JBill

What do you consider "highway speed"? Highway speed around here is seventy to eighty mph.

I can travel 40 MPH but can't go over that without starving. I have tried with the gas cap off and it made no difference.

[Chris Haynes]

Originally Posted by Dick Steinkamp

???

Gas floats on water. Not visa versa.

It's good you drained the tank and got the water out. Continue checking for water in the float bowl. It will be on the bottom of the bowl if there still is some.

All I can tell you is that it was a clear liquid floating on top of the yellowish gas.

[Chris Haynes]

Originally Posted by wmws

That could be the problem. Won't run very well on water. Check out all the other good tips to be sure all is in order.

Whatever this clear liquid was is wouldn't penetrate the screen. So it was blocking the flow of gasoline.

[wmws]

So is it full speed ahead now?

[Chris Haynes]

Originally Posted by wmws

So is it full speed ahead now?

I'll let you know as soon as I have it back on the road. Replacing generator and wiring now.

[Chris Haynes]

Back on the road today. Still starving for fuel at highway speed. :-(

[jm29henry]

Could your float be set to low ? If you turn the gav to the left making it run richer .?

[BILL WILLIAMSON]

With 1/2 tank of gas in Minerva, she would flow a 6" stream of gas at the disconnected gas line. I was using only a Pencil Filter & a Cast Iron Sediment Bowl.
Bill W.

[wmws]

With all the good advice and guesses about your problem I don't think anyone has mentioned your main jet. It could be partially blocked. You could try taking your carb apart and giving it a good soaking and blow job especially the main jet. Just a thought.