Cleaned heat exchanger (soaked in acid)

Our engine overheats after we run it for a while (not right away), indicating reduced (not absent) cooling capacity.  The sea water strainer is clean, we scrubbed the bottom to make sure the strainer mounted over the through-hull is clear, and replaced the impeller.  The next step for us is to replace clogged hoses and clean the transmission oil cooler, engine oil cooler, and heat exchanger.  I purchased muriatic acid at a local hardware store and jon did the deed of removing the heat exchanger, flushing with water, then soaking in acid, and flushing with water.  He could tell that it made a difference just by looking at it.  He is currently working on the hoses and other elements, so I can’t report on the result yet.