Hmm. Is the pump primed? You don't want the pump to run dry.
Also check there is no play on the motor mount to the back plate.
Did you use lube on the seal where the diffuser slides in to the front housing?
Provided instructions from owners manual. NOTE step 5.
Pump Reassembly/Installing New Seal
1. Ceramic seat must be clean and free of dirt, grease, dust, etc. Wet outer edge of O-Ring with small
amount of liquid detergent; press ceramic seat into seal plate cavity firmly and squarely with finger
pressure (Figure 9).
2. If ceramic seat will not locate properly, remove it, place face up on bench and reclean cavity. Ceramic
seat should now locate.
3. If seat still will not locate properly, place a cardboard washer over the polished face and use a
piece of 3/4" (19mm) standard pipe for pressing purposes.
NOTICE: Be sure not to scratch or mar polished surface or seal will leak.
4. Remount seal plate on motor. Tighten bolts to 60-80 inch-lbs. (69-92 kg/cm) torque.
5. Apply a small amount of liquid detergent to inside diameter of rotating half of seal.
6. Slide rotating seal member, polished face last, over threaded shaft end and shaft shoulder until rubber
drive ring hits shaft shoulder.
NOTICE: Be sure not to nick or scratch polished seal face; seal will leak if face is damaged.
7. Screw impeller onto shaft (clockwise); this will automatically locate seal in seal plate.
NOTICE: On models with impeller screw: install impeller gasket and lock screw (left-hand thread –
turn counterclockwise).
8. Mount diffuser on seal plate; tighten screws to 10-14 inch-lbs. (11.5-16.1 cent.-kg.) torque.
9. Assemble motor and seal plate to volute; be sure clamp is properly seated. NOTICE: Clamp knob can
be located in any position around volute; if it is moved after assembly, tighten knob while tapping
around clamp to assist sealing. Do not move clamp while pump is full of water.
Hazardous pressure. Release all pressure from pump and piping system before working on pump
or attempting to adjust or remove clamp. Clamp may blow off of pump if adjusted under pressure.
10. Reinstall pump base mounting bolts (if used) and prime pump according to instructions on Page 9.