It seems like the fuel might be draining out of the carb when the car (1955 Thunderbird 292 stock carb and fuel pump)  is not started for a few days.   I don't want to install an electric fuel pump.   I ordered a check valve that mounts to the fuel pump.   Has anyone used the check valve?   Any other possible fixes besides the valve and electric pump?

I get this all the time.  Stock 56 carb and  a couple of Edelbrocks. 


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Constant issue for me in south Florida, im thinking its evaporation since its not as much of an issue now that were getting cold. i hard mounted a flow through fuel pump in the flex line between frame and mechanical fuel pump. its like 1.5 psi and since its hard mounted its really loud so i can hear when the floats close. just put a switch on dash for now. i had the parts laying around but when i looked it was around 40 for everything.
Seth

This is just my opinion so other opinions always welcome.  The carburetor is not draining back.  I can say that with confidence knowing that the needle and seat assembly is positioned above the fuel level.  My experience is that the ethanol laden fuels simply evaporate much more quickly than the older non-ethanol fuels.  The premium grade is what I use in my carbureted vehicles simply due to it having only 3-5% ethanol versus the 87-89 octane fuels which have 10% ethanol.

My ’50 with its original flathead has a similar issue in that the carburetor dries up after just a few days of not running.  The fix for it was an electric pulse fuel pump with a toggle switch to push fuel to the carburetor before attempting to start the engine.  Other than the electric pump being used for this purpose, the power to the fuel pump is kept in the off position for normal running.

Lorena, Texas (South of Waco)

Correct.

A BIRD runs hot because of poor engine compartment ventilation (mainly). When the engine is shut-off, it experiences heat soak (coolant is not circulating) and the fuel is boiled out of the fuel bowls. And there is also evaporation happening as there is no EVAP SYS. Ethanol laced gasoline has a lower boiling point than E0 gasoline.

An electric primer pump is the easiest way out. If initiated by a toggle switch, use a spring loaded return to OFF position in case you forget.

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Do I understand that you have the electric pump in the engine compartment ? To me , that is playing with fire.





54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I agree with Ted, but I've read in a couple of places, various people stating that fuel is going from the carb (because it's higher than the tank) back to the tank.  But it does not make sense that the fuel can get by a "closed needle/seat"  Hopefully next week I will run the car, take the lid off the carb and see how much fuel is in the bowl and how long it stays there.  I beleive there is a check valve in the fuel pump that should block the fuel from feeding back into the tank.

Consider it this way ...

The car engine shuts down. Immediate heat soak as there is no air circulation or coolant circulation. The fuel (E-10) begins to boil and is released through the vents as a gas. The floats drop and the pressurized fuel in the fuel line expands and enters the fuel bowls.

Most likely the valves in the pump are not opening/closing correctly due to the effects of the ethanol fuel. It is also most likely fouled (as will be the carb) due to zinc oxide and only who knows what is coming out of the tank.

You cannot use a phenolic carb spacer due to hood clearance (BIRD).

Before start, remove the ACL and look into the carb venturies and see if fuel is puddled on the throttle blades (and most likely the intake manifold plenum floor). Move the throttle linkage and see if any fuel is shot (accel pump). No shot, either the bowls are empty or a bad accel pump.

So you crank the engine hoping for a quick prime. You are abusing the starter with extended cranking and there is also no ignition advance retard feature (to allow easier cranking). That pretty ACL acts as a tent retaining the engine heat around the carb and further exasperating the problem(s).

So, the only true way out is with an electric pump, either primer or transfer (tank to mechanical pump) (ideally with return fuel line for cooler fuel) and a clean fuel system with the proper fuel conditioner. The fuel curve has to be adjusted correctly also (larger jets).

Today's' fuel(s) are formulated for EFI and EVAP, not carburetion.

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100% agree with Kultulz, have found the exact same problems when using E10 gasoline.

Interestingly enough, I recently posted this video https://youtu.be/W88wjkI7UJE. (Aviation gasoline in my 1955 Ford Fairlane, 292 Y Block, Summit Carburetor, mechanical fuel pump)

I ran aviation gasoline for a few months in my old Ford just for kicks and gave a report on what I found. That all may be old news for some, but I enjoyed doing it and learned a lot on my own. One of the benefits of running fuel that has no ethanol is that you do not have the issues of fuel boiling/evaporating out of the carburetor bowls. The engine fires right up every time. Plus, I can let the car sit as long as I want to (within reason) - that gasoline's formula has some longevity and does not break down easily. It is certainly not formulated to run in automotive engines but you can do it in a pinch.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

And there is also the problem of ethanol gasoline experiencing phase separation, during transport, station storage tanks, the vehicle fuel tank and it's occurring using a mechanical fuel pump.

Also, it will eat a cellulose fuel filter leading to carb contamination. Think a scintered bronze filter.

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