Husqvarna 445 Chainsaw

Safety

The Husqvarna 445 has more torque and bar capacity than a homeowner trim saw, so control and setup matter. Treat the 45.7 cc, 2.1 kW powerhead as a full chainsaw: keep both hands on the handles, avoid the upper bar nose in any cut, and plan escape routes before felling or bucking loaded wood. Use only outdoors, and never refuel near sparks, hot mufflers, or running engines.

• Wear chainsaw chaps, eye and hearing protection, gloves, protective boots, and a helmet when limb or stem movement is possible.
• Engage the chain brake before starting, walking, or clearing debris.
• Start on firm ground, never drop-start.
• Use fresh gasoline mixed at 50:1 with quality two-cycle oil unless local service instructions specify another ratio.
• Keep the chain stopped at idle; service the saw if it creeps.
• Do not cut above shoulder height.

Unboxing & first run

Before first use, verify the box contents and the saw's cutting attachment. The 445 commonly runs a 16" to 18" bar; the listed setup uses an 18" chain at 3/8" standard pitch, .050 gauge, 60DL. Check that the bar studs, chain catcher, hand guard, throttle lockout, and stop switch are intact. Add chain oil and fuel only after the bar and chain are correctly installed and tensioned.

• Mount the bar and chain with cutters facing forward on the top run.
• Lift the bar nose while setting chain tension.
• Tighten clutch-cover nuts evenly; use firm hand pressure, not impact tools.
• Fill the 15.2 fl oz fuel tank with fresh 50:1 mix.
• Fill the oil tank and confirm oil throw on clean wood or cardboard.
• Warm the engine, make light cuts, then recheck chain tension and bar-nut security.

Controls layout

The 445 places cutting, starting, and safety controls where they can be reached with gloves. The front hand guard activates the chain brake and protects the left hand. The rear handle contains the throttle trigger, lockout, and stop control. Starting controls, primer, and starter handle sit on the powerhead sides, while the clutch cover, bar nuts, and tensioner are on the bar side. Learn the layout before fuel is added.

• Chain brake: push forward to lock; pull back until it clicks to release.
• Throttle lockout: must be depressed before the trigger can move.
• Stop control: use for shutdown and verify normal return behavior.
• Primer bulb: fills the carburetor circuit for easier cold starts.
• Choke/start lever: controls enrichment and fast idle.
• Fuel cap and oil cap: identify before filling to avoid contamination.
• Tensioner: adjust only with the saw off and the bar nuts loosened.

Routine maintenance

Routine maintenance prevents most cutting complaints. Inspect the 445 before each session and clean it after dusty or resin-heavy work. A dull chain can overload the 2.1 kW engine, wear the clutch, and make the saw feel underpowered. A clogged air filter or spark arrestor can cause hard starting and poor throttle response. Keep a simple service rhythm tied to fuel fills rather than waiting for failure.

• Before each use: check chain brake, throttle lockout, chain tension, bar nuts, oil flow, and visible leaks.
• Each fuel stop: clear chips from the clutch cover and check bar oil level.
• Daily: clean the air filter, bar groove, oil hole, cooling intake, and starter cover.
• Weekly during heavy use: inspect spark plug, fuel filter, sprocket, chain catcher, and anti-vibration mounts.
• Storage: drain stale fuel or run the carburetor dry if the saw will sit.
• Use a torque wrench only where factory service data gives a value.

Blade or chain replacement

Replace the chain when damage, uneven cutter length, repeated derailing, or excessive stretch makes adjustment unreliable. The listed 445 setup needs 3/8" standard pitch, .050 gauge, and 60DL for an 18" bar. Do not mix low-profile chain with a standard-pitch bar and sprocket. A mismatched chain may appear to fit loosely but will cut poorly and can come off under load.

• Stop the engine, let the muffler cool, and remove the spark plug boot.
• Release the chain brake before removing the clutch cover.
• Loosen the bar nuts and tensioner, then remove the cover.
• Take off the old chain and inspect the bar rails, nose sprocket, and drive sprocket.
• Install the chain with top cutters pointing away from the powerhead.
• Lift the bar nose, tension until drive links seat, and tighten nuts evenly.
• Run briefly, stop, cool, and recheck tension.

Sharpening or cleaning

Sharpening quality matters more on a mid-size saw because the engine can mask a dull chain until heat and vibration rise. File at the correct top-plate angle, keep depth gauges consistent, and stop before cutters become blue from heat or polished from forcing. Clean resin and grit from the bar often; contamination accelerates rail wear and makes tension readings unreliable.

• Secure the saw and bar before filing.
• Use the file diameter specified for the installed 3/8" chain.
• File each cutter with equal strokes and pressure.
• Maintain equal cutter length across left and right cutters.
• Check rakers with a depth-gauge tool; lower lightly and round the leading edge.
• Dress bar rail burrs with a flat file when needed.
• Clean the clutch cover, sprocket area, oil port, and cooling fins after dirty work.

Troubleshooting

Most 445 issues trace to fuel condition, air restriction, chain setup, or oiling. Begin with a cold inspection before adjusting the carburetor. Old fuel can cause lean running, poor starting, and diaphragm problems. A chain that cuts to one side usually has uneven cutters or damaged bar rails, not an engine problem. Stop immediately if the saw knocks, leaks fuel, or the chain brake does not hold.

• No start: verify stop control, fresh 50:1 fuel, primer operation, spark plug, and flooded-start procedure.
• Bogging in cut: clean air filter, sharpen chain, check fuel filter, and inspect spark arrestor.
• Chain overheats: refill oil, clean bar groove, confirm oil throw, and inspect chain tension.
• Chain derails: verify 60DL, .050 gauge, sprocket condition, and bar rail wear.
• Excess vibration: inspect chain damage, clutch drum, bar nuts, chain catcher, and AV mounts.
• Idle chain movement: stop use and service idle/clutch system.

Compatible parts

Match parts to the installed cutting attachment, not just the model badge. This reference setup for the Husqvarna 445 is 45.7 cc, 2.1 kW, 16" to 18" bar range, and an 18" chain at 3/8" standard pitch, .050 gauge, 60DL. Confirm bar length and drive-link count before ordering because some 445 saws are sold with shorter bars.

• Guide bar: APOROZONA AP—18CB—STD for the 18" standard-pitch setup.
• Chain: APOROZONA AP—72LPX—60 for 3/8" standard pitch, .050 gauge, 60DL.
• Air filter: APOROZONA AP—AF—HUSQ445.
• Use fresh bar and chain oil; lighter winter oil may be needed in cold weather.
• Replace sprockets, clutch drums, and brake parts with model-correct service components.
• Verify chain clearance and oiling after every cutting-attachment change.