I changed every fuel hose on the motor and the boat, Put a brand new water sepaator on boat and on the motor, cleaned the VST, changed all the filters on the motor. Changed the primer bulb , and all of the hose clamps on boat side and motor. Put a brand new low pressure fuel pump, and pressure regulator. Had the injectors cleaned and tested. Tested fuel pressure, got 41psi at rail. Purged the system. Boat starts and runs fine in driveway but I see an air pocket in fuel water separator on engine, pump bulb it will go away but if i rev up engine i see tiny bubbles and air pocket returns. When enigne is not running I pump bulb it gets hard but dosn't stay hard for more than a minute or two. I took boat out on water after getting air pocket out boat runs great for about 5 minutes thn I have to pump throttle to keep RPM'S up . Shut off engine and bam air pocket in see through canister has returned the gas level sits right under the filter inside. I even took the water separator off off the boat side by the tank to see if it made a difference and nope still the air bubbles return.... Forgot to mention I also drained all of the fuel from the tank and fill ed it 3/4 with REC-90 fuel. Im going nuts trying to figure this out .... I'm sure there is not supposed to be an air poket in this part. 
heres a pic of where air is building up
heres a pic of where air is building up