Question
I have an old pump system. Water pumps through valve into "rotary plunger"
type housing the controls flow into 4 pipes but I believe that I only have 2
zones. When the system is turned on, the plunger system does not switch
flow to the other zone. Used to work in the past but has stopped cycling.
Took apart the plunger set up but nothing seems to be broken/stuck. I'm
lost. House is 8 yrs old and in S. Florida and water is pulled from neighboring
lake.

Answer
I am unfamiliar with this type of controller, and it sounds to be somewhat problematic.  WHen faced with this type of situation, I generally recommend modernization of the system in order to improve funtionality and reliability.  I would recommend you install a new electronic controller and the associated equipment.