1990 Johnson Evinrude "ES" Cross V 88 thru 115, 150 thru 175, P/N 507874, Page 45Get this manual
Throttle Valve Synchronization With the engine idling in NEUTRAL, if loosening the carburetor lever adjustment screws results in better idle, improper synchronization of the throttle valves is indicatedAt idle, the throttle valves in all carburetors must be completely closedIf the carburetor linkage is misadjusted so one carburetor throttle plate is slightly open, it will result in poor quality idle1Remove the air silencer cover to observe the throttle valve action ] 2f41
Loosen the throttle cam follower screwPush the throttle cam follower away from the throttle camThe throttle cam follower must not touch the throttle cam during this procedure
3Loosen upper and lower carburetor lever adjusting screws which allows the returnsprings on the throttle shafts to
4Partially open the throttle shafts and allow them to snap
fully close the throttle valves