1971 Johnson 125HP outboards Service Manual, Page 45Get this manual
TIMING POINTER ADJUSTMENT Engine performance depends on the accuracy of ignition timing and carburetor synchronizationIf major power head components have been replaced, or timing pOinter disturbed, the pointer should be re- checked against the TDC mark on the flywheelTo check and adjust, proceed as follows:
1Disconnect spark plug leads and remove spark plugs2Temporarily set timing pointer mid-way in its adjusting slotSee Figure 4-27AUsing Piston stop Assembly (Special Tool #384887) with rod set to dimension shown in Figure 4-27, install tool in No1 cylinder spark plug holeTurn flywheel clockwise until piston contacts end of tool3Mark line on rim of flywheel opposite timing pOinterNow turn flywheel counterclockwise until piston contacts toolMark line on rim of flywheel opposite pOinter4Using scale, measure the mid-point between the two linesMark the mid-point line on the rim of the flywheelIf the mid-point line and the cast-in TDC mark on the flywheel are in agreement, the timing pointer alignment is correctIf not, proceed to step 55Turn the flywheel to align the mid-point mark with pOinter (DO NOT MOVE FLYWHEEL)Loosen pointer adjustment screw and move pointer to align with cast-in TDC mark on flywheelSee Figure 4-27ATighten adjustment screwMERC-O- TRONIC