I have a 97 Four Winns 205 Sundowner with an OMC 5.7L GLi. Engine used to run at 150F according to temp gage. Temperature has crept up by about 10F lately but is stable. Impeller disintegrated last year. I swapped the thermostat recently and checked the impeller. I removed several broken off impeller blades, which stemmed from the one that failed last year. The temperature is stable but still above normal. To summarize it: I replaced the impeller and the thermostat but the engine still runs 10F hotter than it used to. What else can I check? Or does the engine run hotter when the boat runs in warmer water?<br />Any advise is appreciated.
