polaris pb4-60

First post, relatively new pool owner, but im having an issue with my polaris pb4-60 cycling when turned on. I have a 1.5 hp main pump and when they are both running the polaris turns on for less than 30 seconds then shuts off for the same time and this will continue the whole time its in...

I am rebuilding a PB4-60 Booster Pump and after taking off the motor bracket I have founded this ripped foam 'washer' of sorts just laying loose inside. I have seen similar looking parts (in rubber) called 'water slingers', but reviewing the parts diagram for this pump does not show anything...