The Stovebolt Site Forums The Shop Area Engine Shop Holley/ Webber 2 stage 2 barrel carb

I have been having a problem with a Langdon Holley/ Webber 2 barrel carb set up. I purchased it in 2005 as a complete set with an Offenhauser manifold to install on a 235 straight 6. It ran fine for years, but recently has been stalling out with a load on the engine. Even a relatively small hill will stall it out.
I had the carbs rebuilt. It has an electric fuel pump added. All the lines have been checked and are clear. Fuel pressure is 6 psi.
I finally brought it to a performance shop where they put it on a diagnostic machine. As the put a load on the engine and got the rpms up in the 3,000 range it starts bucking starving for fuel.
The only thing that worked to stop the bucking was to spray carburetor fluid directly into the carbs which would smooth out the engine immediately.
The performance shop is at a loss as to what is happening. He said it was definitely in the carbs. He even tried to isolate it to just one carb, but it still did the same bucking starving for fuel. He thinks it is something in the carbs.
Anyone seen this type of a problem? I am to the point of replacing the carbs with two single barrel Carters.

What is the air fuel ratio at different RPM's. Those carbs are very tunable. It sounds like your main jets need to be checked or sized a little bigger if you air ratio is lean.

20 years of acceptable performance on what was a "wrong" carburetor setup to begin with is much better that I would expect to happen. The carb(s) are worn out. Dual carbs on a stovebolt engine doesn't make good nonsense- - - -either run one carb, or three. Unless you have done a massive amount of internal modification to the engine, including virtually redesigning the cylinder head, the dual carbs serve no purpose. The shape and size of the ports are the limiting factor, no matter how much "improvement" is done to the intake and exhaust system. It's like joining two pieces of log chain with a paper clip.

A single Carter YF calibrated for a 235 will provide all the air/fuel flow the engine can handle, and it will be a LOT more reliable in the process.
Jerry

If you are starving for gas, perhaps the screen in the tank is plugged.

Couple of things to consider. First, are we dealing with a real Ford Pinto Holley/Weber? I ask, because Tom also sold a smaller version that was not a Holley/Weber. Or, did you purchase a real 32/36 Weber and not a Ford Pinto Holly Weber? As to 6 pounds of pressure, little too high. Think more like 3-4 pounds of pressure. Float height is critical with these carbs as they do not have a very deep fuel bowl. Direction of the carb is also important. If you take the carb top off you will see the main jets are at the bottom of one side of the fuel bowl. You want the jets toward the firewall so that fuel is moving toward the jets on acceleration and not away from the jets. Having the jets situated toward the front of the motor can leave you with the main jet exposed on acceleration as the fuel sloshes away from the jets, and as the fuel level lowers a bit, as opposed to flowing toward the jets.

May I ask whose electric fuel pump you are using? And yes, Jammer brings up another critical point that you should check.

Do you actually own a 1953 Lancia. If so, you are a lucky man.