Weed Eater Will Not Idle

After the Weed Eater engine ignites, the carburetor system allows a small influx of gasoline into the carburetor to sustain low level combustion. When the trigger gets depressed, the throttle arm opens and more gas flows into the carburetor. If the engine won't idle on a Weed Eater, too little gas or air is reaching the carburetor.

Most idling problems occur from a decrease in the fuel supply during idling. Many things can cause this problem, but the most common is bad or old gas. Bad or old gas will dry out in the fuel tank, fuel lines and inside the carburetor. After it dries, the gas will leave behind gummy deposits that gradually choke the fuel supply. For this reason, never store the Weed Eater with fuel still left in the tank or carburetor. Replace fuel hoses and fuel filters once a season and never use mixed gas that has sat for more than 30 days.

To get the Weed Eater idling again, adjust the carburetor's idling speed. But first, the fuel system will need to be checked and cleaned, if necessary. Pour out any old or bad gas that has sat in the tank for more than a few days into an approved fuel container. Inspect the inside of the fuel tank, the fuel filter and fuel lines for heavy buildup, gummy deposits or anything that might suffocate the carburetor. If necessary, replace the fuel lines and filter. Refill the tank with freshly mixed gas using a 40-to-1 gas to two-cycle oil ratio.

Another common, possibly unseen, cause of these idling problems occurs when too little air is mixing with the gas. The carburetor needs to pull clean air in and mix it with the gas; otherwise, it won't ignite properly in the cylinder. Air filters, which sit on top of the carburetor, clean out the air before it enters. However, these foam pads will get dirty quickly, even after one use, so they need to be checked and cleaned regularly. Wash the pad in dish detergent, rinse it under cool water and let it dry completely.

With the gas supply refreshed and the air filter cleaned, you can safely adjust the idle speed on the Weed Eater's carburetor. The carburetor's idle screw is usually located on the carburetor, on the left side, in between the air filter box and the power head. Start the engine and let it run on a high idle for at least 10 minutes before adjusting the idle speed. Use a small screwdriver to turn the screw clockwise until the head begins to rotate. When the head starts turning, move the screw counterclockwise until it stops. Move the screw clockwise again up to the highest speed possible before the cutting head spins. If this doesn't solve your idling problems, take the Weed Eater to a mechanic to adjust the rest of the carburetor's screws.