So it seems my 382sr1 has a suction type bilge system under the cabin step. Similar to what would be in a jetski hull. Maybe it sucks out the rear of the boat somehow when at slow speeds? Anyone else have any insight on this ?

I am not referring to the sump pump setup .

I'm not sure what suction type means, but if it's the same as the cabin step on the 292 and 353, then there is a hole in there that connects to a hose to a hole in the engine bilge. When on a lift or trailer the "step bilge" can be lower than the engine bilge, and water comes through the drain hose.

Since mine lives on a lift when not in the water, I plugged both ends of that hose. Under the step is smaller. I think 1/2" I then used a small 12v shop vac to just suck the water out. It used to flood the floor of the cabin. Now I get just a bit of water in there with no flooding of my cabin.

Maybe siphon bilge is the better term for what im talking about. Link is to a pic of similar to what is under my step..
Also, I dont see that the 353, 357 and 382 boats have an actual drain tube from this compartment to the engine bilge.

https://www.bonanza.com/listings/Kaw...MaAvxmEALw_wcB

Are you maybe thinking of the pump for your sink? Your sink drains into a box under the step and is then pumped out the back of the boat. If I remember right there is just an open tube that runs water from under step the the bilge.The best thing to do is block it off under the step and at the other end in the bilge. When your boat is on a trailer or lift it can do the opposite and let water go from the bilge to under the step.

Its a diaphragm bilge suction pump as I remember mounted on the starboard side of the engine compartment. Lift the switch and listen for the pump running.