I bought a 2013 waverunner this spring and suspecting that this is filled with salt corrosion. The ski has 151 hours and runs great for about 20min and then overheats. I have flushed it out with a hose and it runs cool on the trailer. I checked the inlet and its clear too. BUT when you run on the lake JUST the engine block get really hot and it overheats. The left pisser is flowing water but it overheats.I Is there anything I can do? Or is this a very expensive engine teardown to get the salt out?