Following was sent this morning:
The fountain is working fine, lots of pressure. The main valve for the entire system was off. The problem with it running then slowing down to a dribble is consistent with the main valve in the off position, with a small leak, pressurizing the pipe for short operation only.
What I did not get to tell you is the back flow valve is leaking, especially so when the water was off. The leaking part is the 6" plate with 6-8 bolts holding it together, looks like some sort of diaphram.
Probably is a good idea to get the part numbers so we can replace them next time