VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Rochester carb leaking, engine will not start

I have a 1939 car, 216 engine with Rochester carburetor. The engine will not start, and fuel is leaking under the manifold (seems that it is coming out from the exhaust donut). But if I pour a cup of fuel directly into the top of the carburetor, the engine starts, and then runs properly.
Carburetor was renovated some years ago, but float was not changed.
What is the most likely reason of this problem, could the float be defective?

The fuel bowl is overfilling. Could be the float is sinking or there is dirt under the needle valve.
After it is repaired change the motor oil as it now contains an excessive amoutof gas.

Thanks.
But if the bowl is overfilling, why does it even help to pour more fuel directly to the carburetor. Shouldn't this give more overfilling?
Yes, I will change the oil after the problem is solved.

Problem solved, but it was not the carburetor. After using the starter too much the last days, I decided to full charge the battery. After charging some hours, I tried to start once more. And engine surprisingly started at first kick and is running fine.
It seems that the battery had enough power to turn the starter, but not enough power to make ignition.
Could this indicate there is a problem with any component in the ignition system?

Apparently you didn't have enough ignition voltage to fire the plugs. Many cars do this when the battery is really low. Voltage is above 6V while running and charging, but quite a bit below while cranking. Spark will be weak because the ignition is made to run on the higher (running) voltage.

To make things the best they can be, check voltage at the (+) coil terminal with the points closed, compared to battery voltage (measured at the same time). See if you are losing a bunch of voltage in the ignition switch or connections.

If that is ok, just make sure your ignition parts are good, spark plugs gapped (and not rounded off), good condenser, carbon button in distributor cap is ok, etc.

Sundfar
I would also suggest you check battery condition and connections. My experience is the AVERAGE battery life is 4 to 5 years, if it needs charging regularly it may well be getting ready to be replaced. Clean all connections between battery and starter motor and has heavy wire.
Tony

If the battery cable has been changed in the last 25 or so years, the wire may be too small. Virtually all vehicles have been 12v for so long, the FLAPS won't carry a 6v cable. Using a cable with insufficient ampere capacity will result in low firing voltages.

I have temporarily "solved" lots of "carburetor" problems for customers simply by hooking up a set of jumper cables on the car.

Jon.

The 6V- battery was changed in 2018. The previous battery was more than 12 years old, but I never had this problems then. I am now investigating if there is a charging/regulation problem.

Sundfar with the battery that new charging may well be the issue. The charging system doesnt do its job as quick as the modern systems so needs to run a lot longer for the same effect.
Tony