How you will find the flow of a pump without any nemeplate or data ?

Just Collect Pumping fluid in a barrel and count the time.Then measure how much liters or Gallons of  fluid collected in barrel  with in one minute.You will get ltrs/min or GPM

just couple the pump and connect the prime mover to a pulse counter (which will give you singe pulse per rotation ) put the delievery (output) into the scaled jar ,run the pump for a while and devide the quantity by the number of rotations (after subtracting the quantity of oil in the delievery line )

so it the method to get the displacement of a pump.