So I've read a few posts here and on a couple of other forums about rinsing the raw water side of the engines / genny / A/C with a diluted Phosphoric acid solution. I want to do this on all my raw water systems. Air conditioner seems easiest (and for sure required for mine as the flow is very low and I discovered barnacles inside my strainer). Generator seems a little more difficult due to access, but the complexity is not to much. The engines seem more complex as I was hoping to circulate the solution throughout the entire cooling system (heat exchanger, trans cooler, oil cooler, cool fuel) and wanted to circulate it in the reverse direction. Here's the question: How do I connect the supply and return line of my home built "port o flush" without flooding the solution into the exhaust manifold? My thought was to connect the supply line to the hose supplying cooling to the exhaust manifold (the one on the bottom (no water rails), disconnect from the manifold) and plug off the opposite manifold. Connect the return to the hose that is normally connected to the output of the raw water pump. Water (or Phosphoric acid) inside the cylinders would be bad.