1993 Johnson Evinrude "ET" 40 thru 55 Service Manual, P/N 508283, Page 50Get this manual
Maximum Spark Advance Adjustment Run the engine with the proper test wheelDo not run the engine with propeller or flushing adapter for the adjustment1Connect timing light to the top cylinder's spark plug leadMark the flywheel timing grid at 19 BTDC2Start the engine and allow it to reach normal operating temperatureRun the engine at no less than 5000 RPM in FORWARD with timer base fully advanced3The engine's timing pointer must align with 19 BTDC on flywheel's timing gridMaximum Spark Advance 45, 55
necessary, by removing the forward socket from spark lever
ill partsAdjust the length of the spark control rodas
4Stop the engine to prevent contact with rotating
Rotate the socket in clockwise direction to advance timing or in counterclockwise direction to retard timing'Two revolutions equal approximately one degree of timingon the spark lever and verify maximum spark advance following Steps thru 3