A weed eater lawn trimmer uses a gasoline engine to deliver power to the piston and crankshaft. When the engine doesn’t accelerate well, drops off when maxed out or dies when idling, a problem with the gas is occurring. The fuel must maintain a consistent flow at all times or the engine will lose power.
Clean Air Filter
The fuel mixes with air before it goes to the cylinder for ignition. The balance between air and fuel must be exact for the fuel to burn at the proper temperature. If the airflow becomes restricted this balance will be off, the fuel mixture will be off and the engine will not have any power. Remove and clean the air filter from the air filter box, mounted on most weed eaters, next to the fuel tank and above the carburetor. Wash the foam pad in warm, clean water with mild dish soap. Rinse it out under cold clean water and let it dry thoroughly before reusing it.
Clean Fuel Tank
If the fuel inside the tank can’t reach the carburetor, the engine will lose power very quickly. Debris, grass clippings and other material can enter the gas tank. Floating around in the fuel, that debris can get sucked up against the fuel filter or fuel hoses, clogging up the system. So if your weed eater is getting power and then suddenly loses it, check the fuel tank for problems. Drain the old fuel and clean the tank with a brush and rag. Pour a little clean gasoline into the tank, swirl it around and drain it out.
Change Fuel Hoses
If dirt or grass entered the fuel hoses it likely will clog up the entire system and cause the engine to lose power. Likewise, impurities in the gasoline, over time, can do the same thing. You must change fuel hoses every one or two seasons, according to your use. Never store the weed eater with fuel left in the tank and carburetor; this will cause the gas to dry out and stick to the fuel hoses and carburetor. Whenever changing the fuel hoses, change the fuel filter as well.
Adjust the Carburetor
After cleaning the air filter, fuel tank and replacing the fuel hoses, you’ll want to readjust the carburetor. The carburetor on a weed eater has three adjustable screws, which control the flow of gas into the carburetor at high, low and idle speeds. If the balance is off or the screws aren’t set right, the engine won’t be getting enough gas and will lose power drastically. Carburetor adjustments can be tricky, so it’s best to leave them to a certified mechanic.