I had the same problem with my twin honda 35's. Previous owner only used the boat a couple times a year, always in salt water. It plugged, on both motors, every hour or so. I would push the wire up the hole to get flow going again. Then I graduated to pulling the cowl and pulling the hose out of its' seat on the outflow end and it would take off. Then the weed wacker line up to the block. One time I actually found a chunk, which I pushed out through the cowl with the weed wacker line. It was salt. I haven't tried salt away yet but will soon. I have it down to where it only occurs maybe every 5 to 10 hours.