Adjusting the 2-cycle outboard motor carburetor will keep the engine running properly while providing better fuel mileage. The 2-cycle outboard carburetor has two adjustment knobs (a large stop screw knob on the left side of the motor and a carburetor idle knob on the side of the carburetor) that allow you to set the carburetor for the best performance in just a few minutes. You can set the 2-cycle carburetor without any tools and save money.
1. Take the cover off the 2-cycle outboard motor, and start the engine, letting it warm up for a few minutes. Set the motor on idle, and determine whether the engine is running too fast or too slow.
2. Locate the stop screw knob on the left side of the motor, and turn the knob counterclockwise to slow the engine down or clockwise to speed up the engine.
3. Adjust the knob until it is close to the trolling speed, and turn the carburetor idle knob — located on the side of the carburetor — clockwise 1/4 turn at a time until you hear the engine begin to stall.
4. Turn the 2-cycle outboard carburetor idle knob back counterclockwise no more than 1/4 turn until you feel the engine running smoothly at the slowest speed possible.
5. Shut off the motor, and place the cover back over the 2-cycle outboard motor.