Acceleration Issues - Weber Carburetor

S

sandbug

Member
1930 Model A Engine
Stock 6V positive
Stock Distributor and electrical systems (Champion W16Y spark plugs at .35)
Fuel pump, fuel lines, Carburetor, and manifold from Arizona Ford
Weber 32/36 DGV used on another ford, and then rebuilt.

Cannot find any vacuum leaks nor exhaust leaks.
This carburetor was rebuilt for a Model A.
We tried 2 other carburetors, and the same issue.

It seems to idle fine, but when stomping the pedal or giving it more gas, it hesitates and flounders and then stalls or backfires.

Any help (other than going back to the original Zenith or Tilison) is appreciated.

https://youtu.be/l2W0mQq8grA?si=ydmM9GkuGws9DRry
 
I'll add. I should have added these facts.
We set the timing with a Nurex timing tool. It was a TDC with both the pin and a visual.
To start the car, we had to pull the spark advance all the way down.

Can I get more initial advance by turning the distributer clockwise or counter clockwise?
 
It sounds like your ignition is very much retarded.

Clockwise. The stock distributor has a pin that prevents it from turning. If your distributor can turn then that makes timing the engine simple. Use the hand throttle to set the engine rpm to a fast idle, about 1,500 rpm. Turn the distributor clockwise until the engine speed no longer increases, then back a little bit. Lock the distributor at this position.

If your distributor has the pin and will not turn then you can do the same thing by turning the rotor and cam a little bit clockwise at a time and trying the engine. It helps to have a degree wheel and timing light to know where you are.

The Weber's acceleration pump and main and secondary main jets are all adjustable. I had to spend several days dialing in my Weber by changing jets.
 
Last edited:
You cannot rotate the distributor much because the copper straps would get messed up. The adjustment is made by rotating the cam under the rotor. Moving it CCW advances the timing.
 
I ended up buying a couple ranges of jets for my Weber to run well in the Phoenix heat and desert climate/altitude. I don't recall whether I went up or down in numbered jet sizes, but eventually I found a pair that wouldn't hesitate or stumble when I punched it to the floor. I think I also changed accelerator pumps inside the Weber. This was almost 30 years ago and a lot of cars have passed through my greasy fingers since then, so I just can't recall the specifics of what I did when Bill Clinton was still President.
I'd recommend buying a couple matched pairs of jets, one pair above and one pair below the numbered jets in your carb. Also inquire of the vendor what his accelerator pump recommendations would be for your altitude and normal temperatures. Also, if you are running an air cleaner, remove it and see if that helps.
Marshall
 
I see now that he said that he has the stock distributor. So it cannot be turned. If he has to use full advance to start then it is way too retarded. He used the Nurex tool to time it.

The Nurex tool should not be use to time the distributor, period. The timing is so easy to set by just observing the points. They should just be opening at TDC. The distributor has a little slack so that the cam can be turned counterclockwise to observe the points opening. When the rotor is as far clockwise as it will go the points should be closed. First the points gap should be checked. 0.020. The advance lever should be up at the top.
 
Last edited:
A friend of my put a Webber on his A, would start and idle just fine but would not accelerate. Finally towed the car to a carb expert. He had it 2 days and found a casting flaw, a passage in the carb body was not drilled out! the car runs fine!!
 
Herb Concord Ca said:
A friend of my put a Webber on his A, would start and idle just fine but would not accelerate. Finally towed the car to a carb expert. He had it 2 days and found a casting flaw, a passage in the carb body was not drilled out! the car runs fine!!
Click to expand...

I bet your friend did NOT have a Webber carburettor but one of those Chinese copies. They are notorious for that sort of thing.
 
Synchro, the owner has passed on, I have no idea who he bought the carb from, but it came with a manifold, so maybe a kit as a opposed to just get getting a Webber somewhere.
 
Make sure the linkage from your distributor to the adjusting lever on your steering column moves freely and travels the full distance, both directions, within the notch on the distributor body. If not, the adjustment lever will not function properly. That can be adjusted on the steering column near the box. Les Andrews addressed this issue on one of his videos.
 
A centrifugal advance distributor (with 14 degrees of built in advance) set to 25 to 30 degrees max depending on compression falling back to to 10-15 degrees initial timing should wake your engine up.Always use a timing light while running with a scale next to the front pulley to set the timing.
 
Last edited:
You must log in or register to reply here.
Back
Top