Identify which grate has the debris in it and shut that motor off. Cruise slowly on one engine so the water flow can push it out. If that does not work then you can start the motor that is affected and throttle quickly forward and reverse and 90% of the time it will clear. What most people don't realize is that with the jet pump setup, when something is sucked up and you can hear the cavitation or feel the vibration, the damage is already done.