Fuel pump problem (Mallory 140)?

[Mike Braddock]

Mr.Fixit,

The tank has had a liner installed (professionally) but no foam. If I turn the pump off for 5 minutes and back on, the pressure is still low, so I don't think there is any problem with debris getting stirred up. Besides, wouldn't it get trapped in the fuel filter and the pressure would be lower all the time?

I have 13.8V until I turn on my electric fan (a big Spal unit), at which point the voltage drops to around 12.2V. What would cause a regulator to function like this? It's just an adjustable check valve, correct? If so, it should either work or not unless I am missing something. Is there a way to check the regulator? I have spoken to some others who say they have the same problem when idling for a long time but they have never had any problems when driving. And they're using the same liquid filled gage as I am (by coincidence), so maybe it's a gage prob??

I didn't have any time to work on it yesterday, but hopefully tonight. I'll let you all know what I find out.

Thanks again Aumore. The pickup and lines are all horizontal and gravity fed, so that shouldn't be a problem...

Mike