Round silver ball on the inlet side of the fuel pump

"The fuel pump on my friends 4

"The fuel pump on my friends 454 Crusader V8 is equipped with a round silver ball on the inlet side of the fuel pump. I'm not certain what it is but I'm guessing it's some type of damping mechanism (similar to what plumbers install on water pipes to prevent water hammer) so that in rough seas the fuel pump won't be subjected to heavy fuel surges.
Am I correct or does this ball serve another purpose?
I'm asking because the engine has been having apparent fuel supply problems that makes it appear to run out of gas after a few minutes of running at 3000rpm (but it runs fine at 2000rpm). The engine has brand new fuel/water filters and I've found no other fuel/water filters in the system with the possible exception of the mysterious silver ball on the side of the fuel pump. I've also checked to make certain any shut-off valves in the system are wide open.
I'm thinking that the valves inside the fuel pump are leaking so that at higher rpms the pump is not able to keep up with the engines fuel needs (I've checked for a leaking diaphragm and the diaphragm seems okay). Also, I realize that there may be a small filter inside the carburetor fuel inlet, but I also know that that filter has a bypass mechanism should it become clogged.
Steve"

"May be a check valve - hard t

"May be a check valve - hard to say as there are many different brands of pumps used over the years.

A fuel pressure gauge will give you an indicator of the pump's health. Could be diaphragm is old and stretched or the flapper valves aren't seating. If you change it, make sure you get a marine grade part.

The filter under the inlet fitting is fairly coarse unless somebody put a bronze one in. Good idea to change it regularly, too."

"Steve,

I don't think t

"Steve,

I don't think there is a bypass on the fuel filter in the carb. So definitely check that. Also you might have a problem with your anti-syphon valves on your fuel tanks. Maybe it is not releasing properly causing low fuel supply."

"If its the original rochester

"If its the original rochester, there's a spring behind the filter under the inlet nut. If the pump's making pressure and the filter's clogged, the spring will compress, and the filter will lift off the gasket.

Could be the ASV acting up, too....they cause all kinds of unusual actions when they aren't working correctly."