Compression Problems

• 1). Remove the air filter cover with the screwdriver. Wash it in warm soapy water, and allow it to dry completely before replacing it. Buy a new filter if the old one is too dirty to even clean.
  
  
• 2). Take the muffler cover off with the screwdriver, and pull out the spark arrestor screen. Scrub this screen with the wire brush and soapy water.
  
  
• 3). Look inside the muffler for any debris or clogs from a heavy buildup of carbon deposits. Check inside the exhaust port for any cracks or holes. Make sure the muffler is attached properly to the engine.
  
  
• 4). Remove the muffler and replace it if you are still having compression problems. Look inside the piston's cylinder for any cracks or damage to the piston, bore and cylinder.
  
  
• 5). Examine all of the seals and rings on the piston to ensure they are working properly. Check the needle valve inside the cylinder, and replace any parts that are damaged.
  
  

Spark Problems

• 1). Pop off the plug wire with the screwdriver. Use the socket wrench to unscrew and remove the spark plug. Replace it with a fresh one.
  
  
• 2). Insert the new spark plug into the plug wire. Don't connect the wires to the engine, but hold them near a metal point on the engine block. Make sure the connection is close enough to the metal to be grounded.
  
  
• 3). Pull on the starter cord, and look for a blue spark. Check the plug wire, and work back to the starter coil if there's no spark or the spark is a weak yellow.
  
  
• 4). Unscrew the handle from the engine, and remove the entire ignition module. Check all of the wires for any damaged or loose connections. Make sure the circuit is properly grounded.
  
  
• 5). Examine the flywheel key as this controls the timing of the spark. Make sure it isn't bent or broken, and replace if necessary.
  
  

Fuel Problems

• 1). Remove any old gas left in the tank. Pour it into an approved gas container. Spray a little carburetor cleaner into the tank, and scrub the inside with the wire brush.
  
  
• 2). Disconnect the fuel line from the carburetor with the needle-nose pliers. Remove the fuel filter and fuel line from the engine, and replace with new parts.
  
  
• 3). Remove the spark plug, and pour about a tsp. of gas into the spark plug's hole. Try firing up the trimmer. If it fires up, spray a little carburetor cleaner into the neck hole on the carburetor. Let the engine burn off any old gas deposits before using the trimmer again.
  
  
• 4). Take the carburetor to a professional to have it cleaned and serviced if it still won't start. Ask them to install a carburetor kit to improve the overall performance of your carburetor.