How to Adjust the Carburetor on a Weed Eater


Adjusting your Weedeater carburetor is as much a part of spring, as the greening of the winter's grass. Storage of the two-cycle engine, that powers the Weedeater, does require some maintenance before it is called into service. Along with fresh gas and perhaps a new sparkplug, the carburetor may have to be tuned to receive the most efficient use of the machine. Adjusting the carburetor is typically a fast process, and with a couple turns of a small screwdriver the engine will be purring.

Step 1

Identify the two adjustment screws on the side of the small carburetor. Both of the screws are a Philips head type. One screw is labeled "Lo" and the other is labeled "Hi." The Lo screw is for the idle adjustment and the Hi screw is for the full throttle adjustment.

Step 2

Turn both screws in a clockwise direction. This will fully close the screws against the carburetor's internal seat. Do not force the screws closed; use a gentle touch to the small screwdriver.

Step 3

Loosen both screws, 1 ¼ turns in a counter-clockwise direction. This is the starting point for almost all two-cycle engine carburetors.

Step 4

Choke the engine. Pull the start cord. The engine will start if there is fresh mixed gas in the fuel tank and a new sparkplug in the engine.

Step 5

Allow the engine to warm up for one minute. Do not adjust the Lo screw as yet. The engine will run a little rough, which is normal.

Step 6

Turn the Lo screw counter clockwise a ¼ turn. The engine should begin to smooth out. If it runs too rough, turn the screw back to the original starting point. Wait 10 seconds. Turn the screw ¼ turn clockwise. Make minor adjustments until the idle smoothes out. Various engines and gas mixtures will require minor adjustments to the two-cycle engine.

Step 7

Depress the throttle a few times. Allow the engine to go back to idle. Wait 10 seconds. Hold the throttle wide open. Turn the Hi screw counter clockwise a ¼ turn. The engine should smooth out. If it becomes too rough turn the screw back clockwise.

Step 8

Allow the engine to drop back to idle. Depress the throttle quickly, several times. The engine should rev up, and then go back to idle smoothly. Make minor adjustments to the screws as applicable. Turning the screws counter clockwise opens the fuel orifice, which allows more fuel into the carburetor. Turning the screws clockwise closes the orifice, which restricts fuel into the carburetor.

Step 9

Keep the screwdriver in you pocket to make final adjustments as you use the Weedeater.

Tips and Warnings

  • Always use mixed, oil and gas, fuel in a two-cycle engine. Failure to do so will permanently damage the engine. Follow the engine manufacturers specifications for the correct gas to oil ratio.

Things You'll Need

  • Small Philips screwdriver


  • Greater Southwest Aero Modelers: Walbro Card Tune Up
  • Small Engine Weedeater Adjust 2-Stroke Carbs
Keywords: weedeater tuenup, two cycle engines, adjusting carburetor

About this Author

G. K. Bayne is a freelance writer, currently writing for Demand Studios where her expertise in back-to-basics, computers and electrical equipment are the basis of her body of work. Bayne began her writing career in 1975 and has written for Demand since 2007.