Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 134Get this manual
WIRING DIAGRAMS
ENGINE OVERHEAT a
The system is activated when the engine temperature is too hotThe TEMP light (a) will come on and the warning horn begins soundingThe warning system will automatically limit the engine speed to 3000 RPMAfter the engine has cooled, shift the outboard into neutral to reset the overheat circuit
IGNITION COIL, SENSOR, OR INJECTOR NOT FUNCTIONING