Typically when you have a priming issue it's due to air being sucked in beacause of a bad o-ring or a leak around the threads of the adaptor which fastens the pipe to the inlet of the pump.
I'm not familiar with that pump, does it have an O-ring around the snout of the diffuser?
When you place the suction inlet under water it should prime even if you had a leak around the inlet adaptor threads.

See ya,
Kelly

Hi:
Thanks for your reply.
I didn't mention that I had cemented the impeller to the motor armature as the repair I made. BAD decision as i discovered after several days of playing around. The air at the inlet still confounds me. Anyway, I undid the repair so the impeller floats as originally designed and I no longer have the problem. Pump primes and now works just fine as it did before.
Thanks again.
Richard