Gas gauge keeps reading lower every day vs last?

[Secret Chimp]

No, this isn't as dumb as a question as my subject sounds...

I know the gauges need to warm up some, but this seems different. Ever since I fixed my gas gauge (non-existent float) I've noticed that the fuel level when I park one day and then vs when I fire it up the next is lower.

For example, yesterday I parked with the needle a hair below the quarter mark. I started it today and it's a hair off empty. It came up a little bit, but not to where it was yesterday.

What gives? Surely I'm not losing a half gallon to evaporation or something. This is a non-emissions car - two vent hoses from the tank up to the filler neck and a single fuel line. I never have "dry bowl" problems with my carb either.

 

[Mopars & Missiles]

Float leaks, its filling up slowly with fuel.

Pretty soon it won't be a float, it'll be an anchor.

 

[Secret Chimp]

It's read full the last three times I filled up over the last month and a half. I had the sender back out a month after I fixed it to repair a bad repop sender seal and I checked the float (small fuel filter that I melted the ends shut on) and there was no gas in it then.

 

[Meep-Meep]

Just a thought, those gauges are sensitive to voltage, so perhaps if you have a voltage limiter acting up that could vary the voltage input and give a different reading. What about the voltage regulator itself? If you have voltage spikes in the system that might explain it too. I'm thinking you have a 69 or earlier single field charging system? If so those are notorious for flickering lights, etc..

 

[Secret Chimp]

I do, it's the original alternator and voltage regulator. I'm starting to get a flickering dome light at cold idle but it just acts marginal otherwise (lights yes, wipers yes, lights/wipers/fan or any combination not so much unless I'm moving)