1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 67Get this manual
4To adjust, stop the engine and loosen the spark advance lever screwI nsert tip of screwdriver between notches of lever and powerhead Twist the screwdriver and move the lever5Tighten the spark advance lever screwRecheck the timing adjustment Adjust the Engine Idle Speed
On remote start modelsremove both remote control cables from the engine before adjusting the engine idle
Check the idle speed adjustment if the engine does not idle at recommended rpm (boat should be floating for normal oper'" ating conditions with the correct propeller installed)Tie boat securely at slip or dock to prevent forward or backward motion1Start the engine
2Adjust the idle speed to the recommended rpm with:
boat in water for normal operating conditionsengine running at normal operating temperatureshift lever in "Forward" gear position
3The idle rpm should be checked using shop tachometerTo obtain the most accurate results the engine should be test run in the water on the customer's boatIdle speed should be 750 rpm 50 rpm in forward gearAdjust idle speed by turning idle adjusting screw4Some motor installations may require additional adjustment