Adjusting the slow speed on a 6 HP Johnson outboard motor regularly will keep the engine running efficiently and provide better fuel economy. The slow-speed idle adjustment screw, also referred to as the low-speed needle, is located near the front of the outboard motor carburetor. The slow-speed idle adjustment screw can be adjusted in just a few minutes with a screwdriver, saving you time and money.
Turn the slow-speed idle adjustment screw clockwise with a screwdriver until the screw is seated without over-tightening the screw.
Adjust the slow-speed screw by turning it counterclockwise 1 1/2 turns with a screwdriver to find the starting point for further adjustment.
Start the outboard motor and let it warm up for about five minutes. Set the throttle at a slow trolling speed.
Adjust the slow-speed idle by turning the screw clockwise 1/4 turn at a time until the motor begins to stall; then turn it back counterclockwise 1/4 turn to find the proper setting on the 6 HP motor.