1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 65Get this manual
Synchronization of the Throttle Valves For proper initial adjustment, all throttle valves in each carburetor must be completely closedIf the linkage between carburetor is misadjusted so that one carburetor has the throttle plates slightly open, this will result in erratic idle and poor quality idle1Remove the air silencer cover to observe the throttle valve action2Retard the throttle lever until the throttle cam roller does not touch the throttle cam3Turn idle adjustment screw to allow mm (116") clearance between screw and stop 131
Loosen upper and lower carburetor lever adjusting screws which allows the return springs on the throttle shafts to fully close the throttle valves5Partially rotate the throttle shaft open and then allow it to quickly snap to the closed position to be certain the throttle valve is closed in the throttle borePress lightly on tab of the adjusting link to remove backlashTighten the adjusting screwMove the cam follower and check that all throttle valves start to rotate at the same timeSynchronization of the Throttle Cam 1Remove throttle cable from the throttle lever