Cooling system problem

[BnTLyons]

Hi everyone! New jet boat owner here and have some questions about what I believe to be a cooling system problem. Trying to do some troubleshooting and noticed that when flushing the port engine, water exits the pisser, the impeller/gear area and this black hole to the left. When flushing the starboard engine, water does not exit through that black hole. I would use proper terminology if I could find a maintenance manual. I’m not very mechanical. Any ideas?

 

[F.M.]

Pictures would help, but I imagine that the black hole you’re talking about is the exhaust.