How to Adjust a 2-Cycle Outboard Carburetor

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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.

Step 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.

Step 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.

Step 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.

Step 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.

Step 5

Shut off the motor, and place the cover back over the 2-cycle outboard motor.