Fishy...You might want to pm Acrylic51. I believe he has serviced/rebuilt some of the sequence pumps. It does sound like a maintenance issue. even if it 'turns over' this time it sounds like it may give you a problem soon. Also, the sequence people are excellent to deal with on the phone.
I run two hammerheads and have been very happy with them. Sequences are quite rebuilable/serviceable I understand.