Bad fuel pump? 51 Custom

[Bob C]

I looked in my Stant catalog and Sacramento Vintage and they both
show vented.

Bob

[Planojc]

Drill it.

[51 MERC-CT]

This is the vented cap that's on my '51 Merc., don't se any reason that the Ford would be different.

[Old Henry]

Here's the one Mack's sells for Ford.



It is, indeed, vented. No sign the one I have is. Better get one.

[JSeery]

Might try driving it with the cap off or loose and see if venting the tank solves the problem. Or as Planojc suggested, if you are replacing the cap anyway drill a vent hole in the existing one until the new one shows up.

[George/Maine]

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I had running problem few weeks ago 8ba.The last thing I did was blow back to tank with 40 lbs and till I heard bubbling and replaced with new fuel pump. Runs good now.

[48 coupe]

loosen the cap ,or take it off and plug it with a shop rag. test drive it for a week.

[Old Henry]

OK. So, in response to all suggestions, here's what I've tried and the results:

1. Ran with the gas cap off just in case the non-vented cap was the problem. Still died.

2. Wrapped the fuel pump, hose, and tubing going to it in a wet towel in case it was vapor lock. Still died.

3. Took the hose from the gas tank fuel line to the pump off and checked it for leaks. No leaks.

4. Took the settling bowl off and checked the gasket. It was neoprene like new. Put it back on and tightened the bowl good.

5. Blew through the gas line from the engine compartment to the gas tank 'till I could hear high volume of bubbles just in case it was blocked.

6. Tested the fuel pump for pressure and flow. It had over 4 lbs of pressure and plenty of flow.

Still, after driving it for a just a couple of miles the gas quit pumping to the carburetor. As it was dying before it totally did I got out with it idling and looked under the hood. There was some air coming into the settling bowl and it would still idle. But, any effort to increase the engine speed it starved for gas and died. It was like a plugged fuel filter allowing very slight flow but nothing more. I could start the engine drizzling gas into the carburetor but it wouldn't pump in.

Anything else to try or is it time to spring $50 to replace the fuel pump that tested OK?

(My wife is really really tired of towing this car home.)

[Bob C]

Had a similar problem one time and it was the flex line to the fuel pump.
The outside of the line looked fine but the inside was coming apart
and blocking the line.

Bob

[Old Henry]

It has something to do with heat. When it is hot the gas will not pump even when the fuel pump and fuel lines and flex hose are all wrapped in wet towel, no matter how long I keep the engine running by drizzling gas into the carburetor. But, after it cools down, I can eventually get the gas to pump after drizzling gas into the carburetor long enough.

Any ideas? It really sounds more like vapor lock than a bad fuel pump. But, where is the vapor lock?

[Lawrie]

Henry. the thing you got to fix is the air bubbles going into the glass bowl,at least you can see the problem,
one thing to do is when the engine is running hot and the bubbles are coming into the bowl,take the inlet fuel hose off and block the port with your finger,if the bubbles stop,the problem is down the line some where,if they don't,look at the gasket under the bowl or some other leak in the inlet area of the pump.
Lawrie

[Old Henry]

This 51 Custom is still giving me fits.
I replaced the fuel line so that once the engine is running it runs fine. And it always starts up fine when cold. But, when hot, if I turn the engine off even just to put gas in the tank, the fuel drains out of the pump and the pump won't pump it back up again. I can force it up with my new handy dandy vapor lock quick recovery tool (here: https://www.fordbarn.com/forum/showthread.php?t=174103) but that's a nuisance to keep doing. I replaced the fuel pump with a new one believing that would fix the problem but it didn't. Are both fuel pumps bad or is it something else?