Your water pressure is fine.

I would take the hotter exhaust of and take it apart the best you can and bag it around alittle to see if something is lodged in it. could be casting slag that broke off and clogged or silt even.

I see this all the time where is live as the water is shallow around docks . Blocks and exhaust need flushed to get silt or other contaminents out ever year or two.