Why Won't My Two-Cycle Weed Eater Start?

Starting problems on a two-cycle Weed Eater lawn trimmer range from the minor to the serious and life-ending. So it can be difficult knowing what are small, fixable problems and knowing when to scrap the Weed Eater for parts. Different problems, of course, will manifest different symptoms.

The Weed Eater uses a standard two-cycle spark plug. This plug needs to have the right electrode gap for the spark to fire correctly. If the electrode is dirty or corroded and the gap is off, you won't get a spark to jump. Check the spark first and replace the plug if you suspect it of being too dirty or improperly gapped.

The HT lead wire, which runs from the plug back to the ignition module, can also lose its ability to push a spark up to the plug. Loose or corroded connections will stop the spark. Another wire, the ground wire, runs from the ignition module to the ignition switch. This wire, if it's loose or corroded, will touch metal and prematurely ground the circuit. Check all connections and wires leading to and away from the module.

The coil inside the ignition module acts like a capacitor, as it builds, holds and fires the high voltage spark. This coil can start to lose its efficacy over repeated seasons and countless starts. You will need to replace a bad or old coil to get the high voltage that triggers the sparkplug. Also, the flywheel has two magnets on its outer rim. When these magnets align with the module arms, they trigger the magnetic energy needed to trip the coil into firing the charge. If the magnets are dirty, corroded or improperly gapped, the plug won't develop the electricity needed to get the plug to fire.

The fuel goes from the tank to the carburetor, into the cylinder and any leftover fuel gets pumped back to the tank. This circuit needs to be unobstructed, so all fuel lines, the fuel tank, the fuel filter and the carburetor need to be kept clean. Fuel impurities and old, dirty gas will create a lot of starting problems, as the carburetor will struggle to deliver the precise amount of fuel to the cylinder for combustion. Replace these fuel parts, except the carburetor, on a regular basis.

Life-ending compression problems often lead to complete engine failure. Leaks around the crankcase and piston area will cause the required pressure to fall too low to pump fuel into the tank. When the fuel gets low, the engine starts running hot and you can cause your piston to seize up in the bore. Often, these internal engine problems are expensive and troublesome to fix, so it may cost less to buy a new trimmer than to fix these starting problems.