Spa pump only leaks when it is not running?

[Doctorsandman]

Pool pump and spa pump are side by side - turn them both on and no leaks, turn the spa pump off and it leaks. I have taken it apart and lubed and replaced all gaskets - I can't figure this out??

 

[Jimrahbe]

Doc,

What specifically 'leaks' Does the spa just drain back into the pool, or does the pump lid leak, or is it in the suction or pressure side plumbing.. or ????

Thanks,

Jim R.