Fuel flow issues

[Flygaff]

I have twin 135 optis on a 25 center. The problem.

My primer balls suck down and shut down the engines. The set up.
200 gallon tank going to two 90 GPH racor filters going to two flow scan sensors to the balls to the engines.what I have done so far. Pumped tank out and removed some water. No help. Changed filters. No help. Bypassed flow scans. No help. Changed balls and ALL fuel lines. No help. Changed vent hose. No help.
The problem occurs after I run a little while. I ran out to the old FG bout today. No problem until I was almost back. Same thing last week, after awhile it will just close down. Any ideas? I am at a loss. I know it is somewhere on the fuel side. Maybe there is something floating around in the tank that I can't find???.

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