Troubleshooting your Husqvarna chainsaw will help you isolate the problem area. Once you've isolated the problem you can then decide whether you can fix it or if it needs a professional. Many minor problems can be fixed at home, but some problems are better left to a service mechanic, as you can often do more damage to sensitive engine areas than good. Carburettor problems, compression problems, and internal engine problems will require a skilled mechanic.
Lift the rubber boot of the high-tension lead wire off the spark plug. Unscrew the old spark plug and lift it out using the socket wrench. Install the new plug into the rubber boot.
Hold the wire just below the boot terminal while wearing the leather gloves. Put the Husqvarna onto the ground. Move the master control lever to the "Run" position. Hold the metal tip of the plug 2cm from a grounded metal point on the Husqvarna's engine.
Crank hard on the starter rope four times. Look for a blue spark to cross the metal points. If a blue spark is present, you can rule ignition out as the source of your problem. If no spark is present or it's yellow, you will need to locate the source of your lost charge.
Inspect the boot and wire back to the ignition module, checking for cracks, corrosion or loose connections. Inspect the short circuit wire from the ignition module to the master control lever, checking for cracks, corrosion, or loose connections. Replace any old or damaged wires and repeat the test.
Inspect the flywheel magnets for signs of discolouration; if discolouration is present, replace flywheel. If there's still no spark, the entire ignition module will need replacing. Ignition module replacement should be done by a professional due to the potentially lethal voltage.
Reinstall the spark plug components. Hold the throttle wide open and crank hard on the starter rope three times. Remove the spark plug again and inspect to see if it's wet with fuel or dry.
Check the fuel supply if the spark plug is dry. Use only 50-to-1 90 octane regular unleaded gasoline to two-cycle engine oil that's freshly mixed. Dump out any old or bad gas into the approved fuel container.
Pull up the fuel filter with the metal hook and pull it off the fuel line with the pliers. If fuel filter is dirty or clogged, replace it with a new one. Wash with a mild detergent and reinstall on the end of the fuel line. Check both the fuel lines to make sure they aren't cracked, broken, or covered in a gummy substance from bad gas. Replace the main and impulse lines if necessary.
Retest for the spark plug for fuel. If it's still dry, have a service mechanic remove and pressure test the carburettor.
Unscrew the muffler cover and inspect the muffler if the spark plug was wet with fuel during the fuel systems test. Look for clogs and heavy black carbon build-up on the spark arrester screen and around the exhaust port. Clean the spark arrester screen and muffler. Replace the muffler if necessary.