I have a 1983 Model 470 (4 inch heat exchanger) with no cooling issues up until this year. I think the temp used to max out around 150 to 160, but temp is now maxing out at 190 while running at 3000 to 4000 RPM pulling skiers. Idling engine at 2000 to 3000 RPM will reduce the temp down to 160 oC...
