Re: 1983 john 115 sea horse idle adjustment
It's important to follow the linkage and synchronization steps in Section 1 of your factory service manual before making the final idle adjustments.
The final idle adjustments should be made on the water with the engine warmed and in gear. Target is 650 RPM.
Before making final adjustments, make the linkage adjustments necessary so that the throttle plates are fully closed when the throttle is in the idle position and the warm-up lever is in the normal running position. Assure that the throttle plates are fully closed at idle and horizontal at WOT and perfectly synchronized through the full range of movement.
You may find it easier to adjust the throttle plates with the cable disconnected, then adjust the cable to the throttle so that it slips on without further adjustment.