Running Hot

[wdf]

330 HP Indmar - while idling I noticed white smoke/steam wafting from the exhaust and the temp guage pegged at 220 deg. I shut it off. We checked the impellar and it feels like all blades are intact but we could not replaced it as it appears stuck. How does one get the old one off?

I removed the thermostat thinking it might be stuck. On crankup, the temp was high. However, once speed picked up, the temp dropped. Now, idling, temp will rise and get too hot, but once underway it drops. Any ideas as to whether this is impellar? Maybe it "rams" water when undeway but not at idle???

[wdf]

Follow up-- It was a worn impeller. Johnson 812 model. Replaced it and now runs normal temp.