Yep, that sounds like a clogged filter to me. I had the same problem (buzzing from the fuel pump.) and it was solved by replacing the fuel filter (just the old-style square one).

Isn't the prevailing wisdom that if you switch to the larger (cylindrical) filter that you use TWO filters, i.e. a square one pre-pump and the cylindrical one after?

If you've got no filter before the pump then you're in over my head.

Graham