How to clear a clogged or blocked through hull fitting on a boat. Sea Flush

[@clivestamp1891]

Assume that only works if the strainer is above the waterline?

[@boatcanvas525]

No, it would work either way because the seacock is closed, forcing air out through the discharge. A/C pumps and strainers are mounted below the waterline because A/C pumps aren't self priming. They'll move water once it's in the pump, but they don't create suction like an engine or generator's raw water pump.