Welcome... In regard to the high coolant temps, search the forums for "waterpump", there's a lot of info. Unfortunately many rebuilt water pumps are not set to the correct internal clearances for optimal circulation. Also there's an issue with the divider plate in the pump; if corroded it may not seal correctly.
re: idle; suggest checking all the spark-plugs for proper coloration, [light tan]. If the plugs look good then it may just need carb & timing tuning.
