Set the trimmer's ignition switch to the "On" position if the switch is in the "Off" position.
Check the fuel tank to make sure it has fuel. Add fuel if necessary.
Press the fuel primer bulb five to seven times before starting the trimmer's engine. The primer bulb is a dome-shaped plastic bulb near the trimmer's choke lever.
Inspect the spark plug for cracks and replace it if necessary. Pull the spark plug wire off with your fingers. Loosen the spark plug with a socket wrench by turning it counterclockwise.
Drain the fuel tank if the fuel is old. Place a drain pan under the trimmer. Open the fuel cap and tilt the trimmer to dump old fuel into a drain pan. Fill the fuel tank with fresh fuel.