It seems to me if your goal is to get rid of salt deposits as you say I would run the small motor in a barrel of fresh water with a fresh water hose constantly filling and oveflowing the barrel to keep diluting the water from whatever salt gets disolved into the water.  I would run the engine at low RPMs for the first period of time so it makes little heat and does not exagerate whatever hot spots it might have.  Towards the end of the time I would gradually speed the engine up to wide open and leave it run there for a minute or two and then idle it down to cool off.  During the first idle period I would take a glass and use it to sample water from the pisser and see how it tastes.  Most people are quite sensitive to salt.  Use that as a guide for how long it needs to be flushed in fresh water. I am not sure there is a better solvent for salt than fresh water. Gary Hagstrom Crackerjack a Maine Cat P-47 now docked in Chequamegon Bay