Something not right. Was that a homemade sn?? does the intake have a restrictor in it?? Look inside where the hi pressure water enters the sn. 52 psi should work--how long are the hoses you bought? Try reduction but just doesn't ring true?? Does the pump output have lots of air in it=seal leak. Remove footvalve and stick finger into the input hole,does it meet the metal or a gap between the impeller and the hose input?? Someone might have put in wrong impeller or blockage within the impeller itself. Coat habger will clean-lotza luck-John