1994 Johnson Evinrude "ER" 60 LV 150, 150C, 175 Service Manual, P/N 500611, Page 111Get this manual
Timing Wheel Indexing, Erratic Ignition Internal power pack problems or shorted isolation diodes could cause power pack to fire erratically or continuouslyTo troubleshoot this situation, you must determine that each cylinder is firing at the correct time and no more than once per revolutionSources of intense light can disrupt the optical ignition sensor, causing misfireAvoid running the engine in bright sunlight while the timing wheel cover is removed Do not point timing light directly at the sensor1Start the engine in test tank and run it at the RPM where the problem exists