Stihl BG72 Parts Manual

The Stihl BG72 is a professional-grade backpack leaf blower designed for demanding commercial and residential applications. This parts manual provides detailed diagrams, part numbers, and ordering information for the complete BG72 system, including the engine assembly, fan housing, throttle controls, harness system, fuel tank, and all associated fasteners and consumables. Below are key sections for identification, assembly diagrams, part lists, ordering, maintenance, and safety.

Product Identification & Overview

Key components: 2-stroke engine, centrifugal fan housing, adjustable harness, throttle trigger lock, anti-vibration system, and translucent fuel tank.

Component	Description
Engine Model	Stihl BG72 2-MIX Engine
Displacement	72.2 cc
Power Output	3.4 kW (4.6 bhp)
Impeller Type	Centrifugal fan, metal
Air Speed	Up to 280 km/h (174 mph)
Air Volume	Up to 1,300 m³/h (765 cfm)
Fuel Tank Capacity	4.0 liters (1.06 US gal)
Dry Weight	Approx. 10.5 kg (23.1 lbs)
Sound Power Level	112 dB(A)
Vibration Levels (Left/Right)	2.5/2.5 m/s²

Engine Assembly Parts

Cylinder, piston, crankshaft, carburetor, ignition module, and associated components.

1. Cylinder & Piston: Includes cylinder (part # 1128 020 2001), piston assembly (1128 030 2001), rings, and wrist pin.
2. Crankshaft: Complete crankshaft assembly (1128 040 2001) with bearings and seals.
3. Carburetor: Zama C1Q-S266 carburetor assembly (1128 120 2001) with gaskets and fuel lines.
4. Ignition System: Electronic ignition module (1128 400 2001), spark plug (Bosch WSR6F), and stop switch.
5. Recoil Starter: Starter assembly (1128 950 2001) with rope and pulley.

WARNING! Engine parts are precision components. Use proper tools and torque specifications during assembly.

Fan Housing & Impeller Assembly

Metal fan housing, impeller, fan shaft, and mounting components.

1. Fan Housing: Main housing (part # 1128 200 2001) with air intake grill.
2. Impeller: Metal centrifugal impeller (1128 210 2001).
3. Fan Shaft: Driveshaft (1128 220 2001) with Woodruff key.
4. Mounting Flange: Engine-to-housing adapter (1128 230 2001).
5. Air Tube Adapter: Outlet connector (1128 240 2001) for blower tube attachment.

CAUTION! Always ensure the impeller is balanced and securely fastened to prevent vibration damage.

Throttle & Control Assembly

• Throttle Trigger: Part # 1128 500 2001 with lockout lever.
• Throttle Cable: Control cable assembly (1128 510 2001).
• Master Control Lever: Combination choke/throttle lock lever (1128 520 2001).
• Control Handle: Right-hand handle assembly (1128 530 2001) with vibration damping.
• Trigger Lock: Safety lock plate (1128 540 2001).

Harness & Frame Assembly

Adjustable backpack harness, frame, and mounting brackets.

Harness System: Padded shoulder straps (part # 1128 600 2001), waist belt (1128 610 2001), quick-adjust buckles.

Frame: Metal support frame (1128 620 2001) with anti-vibration mounts.

Mounting Brackets: Upper bracket (1128 630 2001), lower bracket (1128 640 2001) for unit attachment.

Back Pad: Ventilated foam back pad (1128 650 2001).

Fuel System Parts

Fuel tank, cap, filter, lines, and primer bulb.

1. Turn off engine and allow to cool before servicing fuel system.
2. Disconnect spark plug wire for safety.
3. Replace fuel lines and filter annually or as needed.

Parts List: Fuel tank (1128 700 2001), tank cap (1128 710 2001), fuel filter (1128 720 2001), fuel line kit (1128 730 2001), primer bulb (1128 740 2001).

Tip: Use only clean, fresh fuel mixture (50:1 Stihl HP Ultra oil with 89+ octane gasoline).

Fasteners, Gaskets & Seals

Complete listing of screws, nuts, washers, gaskets, and seals.

1. Screws: M5 x 16mm flange screw (part # 9006 003 1610), M6 x 20mm (9006 003 2010).
2. Nuts & Washers: M5 flange nut (9006 003 0505), lock washers, flat washers.
3. Gaskets: Cylinder base gasket (1128 800 2001), carburetor gasket (1128 810 2001).
4. Seals: Crankshaft seals (1128 820 2001), bearing seals.
5. Clamps & Retainers: Hose clamps, cable retainers, vibration dampers.

WARNING! Always replace fasteners and seals with genuine Stihl parts to ensure proper fit and safety.

Maintenance Parts & Kits

Common replacement parts and service kits.

Kit/Part	Part Number	Description
Air Filter Kit	1128 900 2001	Pre-filter, main filter, cover gasket
Spark Arrestor Kit	1128 910 2001	Muffler screen, gasket, screws
Fuel System Kit	1128 920 2001	Fuel lines, filter, primer bulb
Impeller Repair Kit	1128 930 2001	Impeller, shaft, key, seal
Vibration Mount Kit	1128 940 2001	Complete set of anti-vibration mounts

Exploded Diagrams Reference

Refer to official Stihl BG72 Exploded View Diagrams (Diagrams 1-8) for visual part location and assembly order.

Diagram 1: Engine Assembly (Sheet 1 of 2)

Diagram 2: Engine Assembly (Sheet 2 of 2) & Fan Housing

Diagram 3: Throttle & Control Assembly

Diagram 4: Harness & Frame Assembly

Diagram 5: Fuel Tank & Air Filter Assembly

Diagram 6: Muffler & Exhaust System

Diagram 7: Blower Tube & Nozzle Assembly

Diagram 8: Fasteners, Seals & Miscellaneous Parts

CAUTION! Use diagrams in conjunction with part numbers for accurate identification and ordering.

Ordering Information & Warranty

Genuine Stihl parts are required for warranty compliance and optimal performance.

• Ordering: Contact an authorized Stihl dealer with part number and serial number.
• Serial Number Location: Stamped on engine housing near muffler.
• Warranty: Limited commercial warranty. Use of non-genuine parts may void warranty.
• Dealer Locator: Visit www.stihlusa.com or call 1-800-467-8445.

Safety & Service Notes

Issue	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, compression	Check fuel mixture, spark plug, compression. Clean carburetor.
Loss of power	Clogged filter, exhaust	Replace air filter. Clean spark arrestor screen.
Excessive vibration	Damaged impeller, mounts	Inspect impeller for damage. Replace vibration mounts.
Fuel leak	Cracked tank, bad lines	Inspect tank and fuel lines. Replace damaged components.
Harness failure	Worn straps, broken buckles	Replace worn harness components per parts list.

Safety First: Always wear eye and hearing protection. Follow all operating instructions in the main operator's manual.

Service: For technical assistance, contact your authorized Stihl servicing dealer.