I'm hoping its just hung up. Is it possible that the solvent the shop used to clean it when they decked it got into the seal/guide and dried it out? I guess I'll make sure all the other valves are fully returning. If they are, can I still try and start it to see if it will return? I thought I was almost done with this god-awful project. Seems I may be back at square one though. If I pull the head again, will I need a new gasket set? How much is a rebuilt head? Thank you all.