Noisy water pump

dufferdj wrote:
Our water pump starts out quiet but then starts to chatter --- almost as if there is air in the line. The first couple of days out this season the pump ran quietly. The water flows smoothly the entire time and I have checked to make sure that the pump is attached securely on the rubber mounting brackets and that the hoses are not hitting the walls nearby. It is a Shur-flo model 4008. Any suggestions as to how to rectify this problem?

Firstly, I'd tear it down, for a good cleaning and lubing before putting it back together and evenly tightening all the bolts. Doesn't take much work and haven't done one yet, without some significant improvement in it's operation. Even brought one or two, back to life.
These things are seemingly bullet proof and more good ones have been thrown out, than bad ones, is my guess.