2004 SR Johnson 2-stroke 40, 50HP Service Manual, Page 117Get this manual
IGNITION TROUBLESHOOTING
Flywheel Indexing
Internal power pack problems could cause 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 revolutionDisconnect the spark plug leads and remove all spark plugsPlace the eraser end of pencil in the number spark plug holeSlowly turn the flywheel by hand clockwise, until the greatest length of the pencil is outside the spark plug holeThis indicates the number piston is near top dead center
Mark on the flywheel rim directly across from the timing pointerLabel this mark "2