1992 Johnson Evinrude "EN" 40 thru 55 Service Manual, P/N 508143, Page 45Get this manual
Maximum Spark Advance
Run the engine with the correct test propellerDo not run the engine with regular propeller or flushing adapter for this adjustment1Connect timing light to the top cylinder's spark plug lead2Start the engine and allow it to reach normal operating temperature 3Run the engine at no less than 5000 RPM in FORWARDThe engine's timing pointer must align with 19 BTDC on flywheel's timing grid 4Stop the engine to prevent contact with rotating partsAdjust the length of the spark control rodas necessary, by removing the forward socket from spark lever
DR2811C
f71 5Rotate the socket in clockwise direction to advance timing or in counterclockwise direction to retard timingTwo revolutions equal approximately one degree of timingf71 6Install the spark control rod on the spark lever and verify maximum spark advance following steps thru 3Idle Speed 1The boat and engine must be in the water under normal operating conditions with the correct propeller installed The boat's movement must be unrestrained The boat must not be tied to dock or trailer2Start the engine and allow it to reach normal operating temperature 3Check idle RPM in FORWARD gear with an accurate tachometer1sl 4Verify that engine idle speed is 750 25 RPM when idle speed screw is against its stopDR2811C