First thing to check is the "polarity" of your electrical connection. The
pump may be running backwards! The way the internal wires in the pressure switch
box are connected can vary between pumps, so the external connection from the
old pump is not a reliable guide. Happened to me!
Regarding the old pump, you should try lubricating and moving the pressure
sensing arms and springs. Also, you can adjust the start and stop pressures to
get the range you want by loosening or tightening the adjustment nuts. Takes a
bit of time, but is not difficult.
MALAIKA II, SM 336