I have seen fuel boil in a float bowl. Or close enough that I didn't want to be around! But, it doesn't make sense to me that you have a fuel bowl filled to specification, and it won't run. The pump obviously filled the bowl, so it is 'out of the picture'.
I had heard of putting clothespins on the fuel line, and have a mental picture of someone going waaayyy over the line, having about 20 pins on about a foot of fuel line.
The ice cubes may have cooled the fuel or fuel pump, but I don't see how it would matter if the float bowl is full.
Putting the choke on will use engine vacuum to pull fuel into the intake, but it should not matter if the carb is working correctly, as the fuel would be pulled into the venturi naturally. This doesn't make sense...
tom

 

Perhaps the fuel bowl appers to be full but may be down a 1/16 or so from full, now the pump is getting air not liquid and can't pump. The level in the carb bowl is down or the engine would run. I have never heard of anyone being able to measure the pressure developed when gasoline boils and is evaporated in a line, however since it causes this vapor lock problem it has to be higher than atmospheric pressure, which in fact is what pushes the fuel from the tank to the slight low pressure created at the diaphragm pump. The placement of an electric pump near the tank would be the best cure, but if I would do this a saftey switch on the oil pressure would be a must. I also might put a mercury switch in line to cut it off in case of a roll over. Had a friend who lost his mother because of a lack of an oil switch back in the late 50's she was a great lady. kotzy

 

I have an old Plymouth with a flat head 6, I had the sme issue. Went threw the ignition ect... I re routed the fuel lines, and put in a fuel pump back by the tank... WHat a difference, and problem solved

 

Got 6 volt pump and low pressure regulator from Speedway Motors. Problem solved. Runs all day in 90+ degree weather, now. I don't know why my mechanical pump couldn't keep up with demand under hard acceleration. Maybe float level is too low but electric pump provides higher pressure/volume. Great discussion!

 

My viewpoint is that the regulation pump is at the HOT end of the fuel system. Put a pump back at the COLD end, and you won't have any more problems. Exactly what, I will leave to the gurus... I don't claim such sainthood for myself.
tom