Sunday on my last run I had a alarm going off. Looked at gauges everything is ok .2 min later looked again and Starboard engine was heating up. Pulled outdrive today and impeller is good. Belt is good also. What next.Alsrm stayed on even when engine cooled. They are 454 with thunderbolt ingnition. No water in oil. Idles fine ran ie to get it on the trailer.It stayed normal temp.