Engine repairs on a Husqvarna chainsaw can be broken down into three basic categories--ignition, compression and fuel system. Other repairs fall into either the drive system or lubrication system. Most repairs for these chainsaws will require replacement parts, which can be purchased at any home and garden store or a Husqvarna dealer. You should only use certified Husqvarna replacement parts. If you're not qualified or don't have small engine experience, it is better to leave these repairs to a professional.
Unhook the rubber boot from the spark plug. Unscrew the spark plug with the socket wrench; remove it from the engine. Refit new spark plug into boot. Hold them close to metal point and pull on the starter cord to determine if a spark is present.
Check the connection between the boot and wire for damage if there's no spark present. Replace wire, contact spring and boot as necessary. Follow the lead and ground wires to the ignition terminal looking for any breakage or damage. Replace wires if damaged, rusted or corroded.
Unscrew the starter cover. Inspect the flywheel for any damage. Check the flywheel magnet's air gap with the ignition module, which should be .3mm. Replace the flywheel if it's sheared or damaged. Check the starter pawls on the flywheel for damage and replace as necessary.
Test the ignition coil and starter to see if they hold a charge. If no charge is present, replace the ignition module.
Clean the air filter and spark arrester screen. Replace them if they're too dirty to clean. Check the muffler's exhaust port for any damage or clogs.
Unscrew the starter cover and inspect the starter cord, pulley and recoil spring for any damage. Replace these parts as necessary. Remove the flywheel from the crankshaft.
Remove the muffler from the engine. Remove the cylinder, piston ring and piston. Inspect the cylinder for any cracks or damage. Inspect the piston for any nicks, dents or damage. Buff the piston with the emery cloth or replace if necessary. Replace the piston ring.
Inspect the seals on both sides of the crankshaft for damage. Replace as necessary.
Get rid of any old gas in the tank. Dump it into an approved fuel container. Clean the tank with the rag and brush. Check the vent hole in the gas cap. Clean the cap or replace if it's clogged.
Unscrew the cylinder cover and remove it. Unscrew the choke cover plate that sits above the carburettor. Disconnect both the main fuel line and return line. Pull both of the fuel lines out through the tank. Replace both of the fuel lines and fuel filter.
Unscrew the carburettor from its mount. Disassemble and clean the entire carburettor. Rebuild the carburettor with a carburettor kit, replacing all of the filters, seals, valve covers, needle valve and Welch plugs.
Replace the gasket that sits in between the carburettor and the crankcase. Reinstall the carburettor. If problem still persists, replace the carburettor.
Inspect the guide bar and chain for heavy wear or damage. Lubricate the sprocket tip on the nose of the bar. Flat file the edges of the guide bar to remove burrs.
Remove the clutch assembly from the engine. Check the sprocket and clutch drum for deep grooves or heavy wear. Replace if they're worn out. Inspect the clutch shoes to make sure they aren't too thin.
Replace the clutch shoes if any section is thinner than 1mm. Make sure the clutch spring engages the crankshaft. Replace clutch parts as necessary. If drive system problems persist, disassemble the crankshaft and crankcase and replace chainsaw if necessary.
Clean the guide bar with the rag. Unscrew the oiler cover plate, which sits above the oil plate. Insert the edge into the slot on the guide bar. Scrape both guide slots on the bar clean with the oiler cover plate.
Check the bar's oiler holes, which sit above and below the notch the guide bar uses to sit on the bar posts. Clean the holes with the brush. Replace guide bar if holes can't be cleaned.
Dump any oil in the oil tank. Clean the tank with the brush and rag. Pull out the oil pickup and oil filter. Replace both parts if they are old or dirty. Pull out the oil hose that connects the tank with the pump and replace it.
Remove the clutch assembly from the crankshaft. Unscrew the oil pump's mounting screw and pull it from the engine housing. Disconnect the oil hose and remove it from the engine.
Disassemble and clean the oil pump. Inspect the oil pump's cylinder and piston for heavy damage or wear. Lubricate both with engine grease before reinstalling the pump. Replace the oil pump if lubricating problems still persist.
Refer to your owner's manual to make sure any of these repairs won't void your warranty.