The cooling system can be at over 200*.
Your underhood air temp can be several hundred degrees. Your engine is sucking all that hot air right down the hatch.
Put an IR gun on your steel line. I bet it's over 100*F,lol.
I think gasoline starts to boil at 95*F, at atmospheric pressure.
Every time your float valve opens, the gas in the line goes close to atmospheric pressure, even if for only milliseconds. But the gas dropping into the carb is already at way over 100*F, so when it scoots thru the valve..... into atmospheric pressure, it is apt to boil right then.
You can pull the top of most Carter 2bbl carbs, and run the engine with them off..... And you can watch the gas boil as it exits the float valves; I have done this and seen it.
95*F.
Your fuel system from pump to valve and carb bowl needs to stay under this.
How is that possible on a 100* day?
It's not.
But there are over 200 compounds in gasoline and only the lightest boil at 95, some don't until nearly 400*F.
The questions are, where is the boiling gas going?, and how can I keep my carburetor under 95* on a 100* day with 200/250Plus degrees air being blasted at it by the fan/
I don't know, but I can tell you what I did;
Step 1; I cut a hole in my hood, and connected the top of the carb to the underside of the hood. Now,on a100* day, the carb gets 100* air. Not 200,not 300,nor even 350* air.
Step 2; I redirected the air coming thru the rad downwards
Step 3; I installed a 3/8 pressed paper gasket under the carb.
Step 4; I installed a 3/8 steel line from the tank to the 7psi pump,then directly to the carb,without filter, or rubber parts; and I routed that line away from hot engine parts.
Step 5; I put a bigazz EFI filter at the back in the airstream.
Step 6; I run 87E10.... with maximum advertised 10%alcohol in it.
Step 7; I run a DP carb, and a sq-top SuperCoil
Now how this works, I think, is like this;
The bigger steel line acts like a radiator, putting the heat into the airstream. The 7psi pump and one piece line from pump to carb maintains the fuel at pressure all the way to the float valves. The float bowls are cooled by the main body, which, as long as the engine is running, is being cooled by pressure change that happens in the venturis, which I'm hoping is aided by the alcohol in the fuel. The paper gasket prevents the heat from coming up from the AirGap intake, and spoiling the venturi cooling.And the air coming down from the top of the hood is at ambient temp.
>I have aluminum heads and naked TTI headers,and my minimum coolant temp is 205*F. It's like blast furnace under there.And finally, I ventilated the hood so that when I turn the car off, the hot air escapes upwards, "pulling" fresh cooler ambient air up from the bottom, by pressure differential; hi pressure air always moves to a low pressure area.
The advantage of the DP carb is that if the car sits for a week or three, a full length stab on the pedal is usually all it takes to fire her up, on the syrup that might be all that's left over in the half empty bowls. And the Accell Bad-Boy coil will light anything.
>I have trouble with carburetor-icing on cold days. lol.
