Lady M: Cooling Water System Rebuild

I had the three heat exchangers brought to a radiator shop to be steamed out, cleaned and pressure tested, as well as the expansion tank. I bought a new thermostat, all new water hoses, zincs, and 50/50 mixed antifreeze. I eliminated the corrosion in all the components, painted everything up, and flushed the engine block. Lastly, I added a new temperature sender to coincide with the new temp gauges for good measures. 

The last time I took “Lady M” out, my cooling water temp was pinned past 220° on the temp gauge. The engine is supposed to run between 170-190° (with the thermostat opening at 174). So yeah... issues. My first thought was a broke raw water intake pump (these should be replaced every year) or a clogged heat exchanger. The impeller looked satisfactory but I replaced it anyways and moved on. I then wanted to look at the belt driven closed cooling water system pump, but after pulling the pump housing off, the issue presented itself. 

The previous owner must’ve mixed antifreeze right before I bought the boat because the entire cooling system was plugged with this jelly-consistency stuff known as “Silicate Dropout”. The dropout would’ve started brewing on my last trip out. This gave me the opportunity to go through every piece of the system and do a thorough cleaning and rebuild.