I have 19 ft. Starcraft with a 115 h.p outboard. Last night while towing a larger boat at slow speed an alarm sounded. I had plenty of oil in the injection system and the motor was circulating water. After towing I ran the boat at high speed but it took 10 minutes or more before the alarm stopped. At the dock I shut the engine down and restarted with no trouble, any ideas ? Could it be just a faulty alarm ? I do not have the manual.