Getting frustrated. Ran this thing for about an 1 1/2 hr. this morning (70°) and the temp climbed to about 250-260. Ran at idle and the temp came back down. I've replaced everything in the cooling system including the head and still running hot. Not sure what to do next.
This is just a wild guess because I don't know a danged this about these machines. That's why I'm HERE... to learn. But that symptom sounds just like what happens to an automotive engine if you take the thermostat out. The fluid stays cool but it's also moving too fast to effectively capture head. Then the water in the head(s) starts to boil. You didn't leave out a thermostat or a flow restrictor when you were replacing parts, did you?