08/02/2026
A steady (solid) warning horn on many OMC outboards may not be from overheating. There is a High Vacuum switch, found on many Johnson/Evinrude engines, that monitors the vacuum side of the fuel system. A kinked fuel line or some other obstruction can cause this switch to activate the audible warning system. This was a very good feature that only OMC had. It can save your powerhead from destruction.