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I know your frustration. Howard has zeroed in on the cause of the problem, no fuel with a sudden drop in the accelerator, stalling. The throttle guard prevented stalling on cars with overdrive. One is prescribed for my '40 Stromberg AAV-26 10-40, but not on yours.

So did you set the needle valves with a vacuum gauge? I think most guys say they can hear when they are set correctly, but a vacuum gauge held to a hole on the EDIT: INTAKE manifold can make setting it/them more accurately.

As you know, I sent my Stromberg to one of the best places in the country, one highly recommended on this site (Daytona Parts), so we Assumed it couldn't be the carb. But they screwed up royally on the float settings. I say royally because that Assumption caused us to add, dismantle, and replace major and minor components for 2 weeks before sticking the old Carter, that has never been rebuilt, back on the car to get it to run. The Stromberg went back for warranty service and returned promptly corrected, and it's perfect. The car runs perfectly now. It's thrilling the way it runs. I know you want that.

Is your idle set to spec or a bit above?

Thanks Howard and Joe,

My car is about an hour away from where I live and so there is a bit of a time delay on answering some of the questions and reporting back with results. Actually, I was going to get rid of the car, as I simply cannot figure this stupid thing out. David, the guy helping me ripped me a new one over that idea and says we have come way too far and done too much to the car to quit now. I have to agree, plus I am totally in love with the old girl and it would break my heart to get rid of her, but the frustration level over this has reached redline.

I don't quite understand what a dash pot is Howard?? Are they electrical or mechanical?? I would be willing to try anything at this point. As I have said ad nauseum, the engine just 'coasts to a halt'. It is the smoothest thing - it just 'runs out of revs'. Not a sputter, not a cough or a backfire; and then 30 seconds later it fires back up and runs and idles perfectly. We have the idle set at just under 600 RPM Joe and than seems like a nice speed. I am going out tomorrow and there is one thing we 'discovered' yesterday that I'll rectify and I will post on that afterwards.

I would be the happiest mortal on the planet if I could get this car to run like it is supposed to and be able to drive around a bit and enjoy it!!!

So did you set the needle valves with a vacuum gauge? I think most guys say they can hear when they are set correctly, but a vacuum gauge held to a hole on the exhaust manifold can make setting it/them more accurately.


???

Joe, don't you mean a vacuum gauge connected to the intake manifold? There is no vacuum present in the exhaust manifold. You should be adjusting idle mixtures to the maximum vacuum consistent with the leanest mixture.

A dash pot is built sort of like a vacuum advance mechanism. A housing contains a spring, rubber diaphragm and a plunger shaft.

In the dashpot the carb linkage would push against the shaft and spring to make the diaphragm move. Behind the diaphragm is a cushion of air which escapes as the diaphragm pushes it out. A bleed screw controls the amount of air leakage and thus the time or force it takes to collapse the spring and move the diaphragm to expel the air.

You would adjust the plunger depth and bleed screw so that as the carb linkage closes the throttle plate, somewhere near the point of complete closure it hits the plunger and makes the diaphragm move. Rather than an abrupt shutting of the throttle and complete choking off of air, it slows the closing enough the engine has a chance to slow down and need less air before the plates close. The theory is the slowdown will prevent a complete stall.

Here are a few of the available shapes and types.

Sorry, Yes, use the INTAKE manifold to measure the vacuum.

Only two things are common for the symptom you describe: fuel starvation or flooding. Other things are possible but seem unlikely. I had thought of a dash pot too but rather than throwing parts at it (especially parts it never needed when new), try to diagnose the problem.

For example, a weak throttle return spring that lets the idle be set at a certain rate but without the linkages fully bottomed out so that it is actually set far lower. When you drive and the system warms up, it closes more tightly and the idle goes below the point where it can run.

You said that all the fuel lines were run away from the manifold and that there is an electric pump at the back by the tank. Did you actually connect a fuel pressure gauge at the carburetor to be sure there isn't too much or two little pressure? Connecting one that you can somehow leave attached temporarily and see while driving might tell you something.

You mentioned, if I recall, using clear fuel lines. Are you sure that the material is actually compatible with petrol?

Are you running the electric pump all the time? Is the stock pump still there and inline? If the latter, try shutting off the electric pump as it really should be used only as a primer to get fuel to the carburetor after it's been parked for some time but the stock pump is excellent for everyday use.

Was the carburetor disassembled and thoroughly checked? Checkballs (if it uses them) and float levels all okay? Needle valves seating properly?

Related to my first example above, you might want to pop off the accelerator pedal and put some silicone grease on the pivot balls to help eliminate it from the equation as a culprit of sticking.

This is simple, just try it. Don't ask why, just try it, its easy. Ask your mechanic politely and just tell him its my "hail mary" suggestion. Everything else he has covered, no doubt. Presume you have tried one or more backup coils.
Wire the power to the coil directly to the starter solenoid battery connection. bypassing the ignition switch, etc. This will take a short length of wire, two alligator clips or better for a test drive. Maybe 20 minutes total.

Just try it. Otherwise you know my other suggestion.

DAF

Joe: I knew what you meant (thanks for clarifying Dave) and we did go and buy a new pressure/vacuum gauge and have checked as per the instructions.
Don: great points.... one thing of note: we did take the linkage apart and found it was not hooked up properly - that is rectified and the accelerator pedal is like silk now and bottoms out at the carb as it should. Plus we lubricated all the moving parts of the linkage. I am running the electric pump only, bypassing the diaphragm pump for now. The 'clear' lines you reference Don are just clear inline filters that allow me to see if I am getting fuel and if it were boiling I expect I would see some bubbles. I do not think that is the cause as it has stalled when not even up to full temp on a cool day. And yes, we did check the pressure and are reading
3 3/4 #'s at the carb which is pretty close to spec. This is the 3rd carb with the last 2 being fresh rebuilds right out of the box with no change in the stalling symptoms so I am loathe to blame it on carburetion

I have one remedy that I am going to try tomorrow and will report on that if it makes any difference. Bear with me.

Quote:

Not a bad idea but if the standard rubber covered pedal over a metal core strongly suggest you reach around and place the linkage rod between two fingers. Put thumb on front side so as to put pressure and squeeze the rubber socket on the back to the metal as you pull the ball out. The old dry rubber socket with no support can break off and leave the pedal useless if you randomly try and pull it loose. If the worst does happen Kanter has new repros.