How to Troubleshoot a Ryobi Weed Trimmer

Put on your work gloves before attempting to troubleshoot any area on the Ryobi. Lift up the rubber boot, wiggling it lightly if necessary, and remove it from the end of the spark plug. Unscrew the spark plug with the socket wrench.

Push the test plug into the rubber boot and clip it onto a grounded metal point somewhere on the engine block. Make sure the ignition is switched to "On." Lay the trimmer on the ground and crank the starter rope.

Check for a blue spark across the electrode gap. If no spark appears, check the HT lead and short-circuit wire for any pinches, cracks or wearing in the outer insulation. Replace any damaged wires and repeat the spark test. If still no spark appears, allow a professional to perform further ignition troubleshooting.

Disconnect the test plug. Leave the spark plug out and boot off. Pull on the starter rope three times. Screw the compression gauge into the spark plug hole.

Hold the trimmer and pull on the starter rope until the compression gauge stops increasing. A trimmer should read between 100 and 140 psi. If compression drops, take it to a professional.

Unscrew the back air filter/muffler cover. Take the cover off the engine and lift out the air filter. Unscrew the choke cover plate and remove it from the carburetor.

Unhook, using your fingers, the two gas lines on the carburetor. Tilt the engine up and look for gas to come out the lines. If no fuel appears, service the fuel system.