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Chainsaw

Husqvarna 445

2-Stroke

The Husqvarna 445 is a 45.7cc 2-stroke chainsaw and the mid-point of Husqvarna's E-series consumer lineup, suited for regular firewood production and occasional felling of medium-diameter trees with 13" to 18" guide bars. The X-Torq engine provides improved torque and fuel economy over the previous generation. The 445 runs a Zama carburetor and accepts the NGK BPMR7A or Champion RCJ6Y spark plug. Parts families overlap with the 435 and 440 within the E-series. Routine maintenance: spark plug, air filter, primer bulb, and fuel system components.

Verify before ordering: Fitment can vary by serial number, production date, region, and sub-model. Match the OEM number and physical dimensions before ordering.

Husqvarna 445 quick specs

Equipment
Chainsaw · 2-Stroke
Covered Parts
Spark Plug, Air Filter, Fuel Filter, Carburetor, Recoil Starter, Ignition Coil, Primer Bulb, Fuel Line Kit, Chain, Guide Bar
OEM References
537254402, 544080802, 503446501, 506450401, 544071604, 573935702, 503936601, 544128601
Model Family
445, 450, 455 Rancher
Data Confidence
Not yet independently reviewed

Quick Fitment

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Tune-Up Kit

Common service bundle: spark plug, air filter, fuel filter, carburetor, primer bulb, fuel line kit.

Maintenance Interval

Inspect filters and fuel lines each season, replace spark plugs during annual service, and service carb/fuel-system parts when starting or idle symptoms appear.

Before You Buy

  • Confirm the full model is Husqvarna 445, not just the family name.
  • Check serial number, production date, and regional variant before ordering.
  • Match the old OEM number stamped on the removed part when available.
  • Compare dimensions, plug gap, thread, fuel line diameter, or chain pitch/gauge where applicable.

Common Mistakes

  • Ordering from a family listing without checking the exact sub-model.
  • Buying a kit that includes the headline part but wrong gaskets, lines, or bulb size.
  • Choosing the wrong carburetor revision when multiple versions were used.
  • Assuming all fuel line kits use the same diameter and routing.
  • Installing the correct plug number with the wrong gap.
  • Matching bar length but missing pitch, gauge, or drive-link count.

Symptoms Map

Won't start

Spark plug, fuel filter, primer bulb, carburetor

Starts then dies

Fuel filter, fuel line kit, carburetor

Bogs under throttle

Air filter, carburetor, spark plug gap

Primer will not fill

Primer bulb, fuel line routing, in-tank filter

Cuts slowly

Chain pitch/gauge, bar wear, drive links

Replacement Options

Best OEM equivalent

Start with OEM references 537254402, 544080802, 503446501, 506450401 and match the removed part before choosing a listing.

Named part options

Cross-check named parts such as NGK BPMR7A (spark plug), Stens 605-414 (air filter), Stens 610-035 (fuel filter) against the OEM number, identity label, and dimensions.

Best for annual tune-up

Bundle spark plug, air filter, fuel filter when servicing the Husqvarna 445 at the start of the season.

Best if replacing fuel system

Compare the fuel filter, carburetor, primer bulb, fuel line kit together so line routing, bulb size, filter style, and carburetor connections match.

Best chain/bar combo

Match chain specs together, especially pitch, gauge, drive links, and bar mount details.

Best budget kit

Use kit listings only when every included part matches this model page; cheap kits often mix correct headline parts with wrong bulbs, lines, or gaskets.

FAQ

Should I buy OEM or aftermarket parts for the Husqvarna 445? Use OEM when the part controls fuel metering, ignition, or safety. Aftermarket kits can be useful for routine filters, bulbs, plugs, and tune-up bundles when the OEM number and dimensions match.

How do I avoid ordering the wrong carburetor for the 445? Match the carburetor number stamped on the removed unit, then compare linkage, choke setup, primer routing, gasket stack, and fuel-inlet direction.

What should I check before replacing fuel-system parts? Photograph the old fuel-line routing, match line diameter and filter style, and compare primer bulb size before buying a kit.

What chain details matter besides bar length? Match pitch, gauge, and drive-link count against the bar stamp, old chain, and drive sprocket. Bar length alone is not enough.

As an Amazon Associate, WhichPartFits earns from qualifying purchases. Match the OEM number, dimensions, and model variant before buying.

Spark Plug

OEM537254402
Dimensions
0.5mm gap
Variant notes
OEM is Champion RCJ7Y equivalent; also fits 435, 440, 450

Air Filter

OEM544080802
Variant notes
Fits 445 and 450 series; also referenced as 544080803

Fuel Filter

OEM503446501
Variant notes
In-tank pickup filter

Carburetor

OEM506450401
Variant notes
Zama C1M-EL37B; also fits 445E, 450, 450E

Recoil Starter

OEM544071604
Variant notes
Also fits 450
  • No named part listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.

Ignition Coil

OEM573935702
Variant notes
Also fits 435, 440, 450; replaces 505427201, 544243801
  • No named part listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.

Primer Bulb

OEM503936601

Fuel Line Kit

OEM544128601
Variant notes
Includes fuel pickup line and return line

Chain

OEMSpec-based fitment
Dimensions
18", .325" pitch, .050" gauge, 72 drive links
Variant notes
Stock bar length; verify drive link count matches your bar

Guide Bar

OEMSpec-based fitment
Dimensions
18", .325" pitch, .050" gauge