Stihl 044 Chainsaw Workshop Mnaual

STIHL 044 1 This service manual contains detailed descriptions of all servicing procedures on model 044 chain saws and can thus be used as a basis for professional overhauls and repairs to all versions of this machine. We recommend that you make use of the exploded views in the illustrated parts lists while carrying out repair work. Most of the illustrations show the in- stalled positions of the individual components and assemblies. Whenever possible you should refer to the latest edition of the parts list for the part numbers of any spares you may require. Microfilmed parts list are always more up to date than printed lists. In the event of faults it is quite possible that a particular condition may have several causes. It is, therefore, advis- able to consult the "troubleshooting charts" for all assemblies and systems when tracing faults. You will find these troubleshooting charts immediately after the specifications. Engineering changes which have been introduced since publication of this service manual are announced in "Technical Information Bulletins". Such bulletins should be treated as supplements to the service manual. This service manual and all technical information bulletins describing engineering changes are intended exclu- sively for the use of STIHL servicing dealers and staff within the STIHL service organization and must not be passed on to third parties. Servicing and repairs are made consid- erably easier if the chain saw is mounted on assembly stand 5910 890 3100 or 5910 850 3100. The saw can be quickly secured to the stand by means of the two bar mounting studs and nuts. While on the assembly stand the saw can be swivelled to any required position to suit the ongoing repair. This not only has the advantage of keeping the component in the best position for the repair but also leaves both hands free for the work and thus helps save time. The "STIHL Special Tools" manual illustrates and lists the part numbers of all available model-related servicing tools as well as general-purpose tools for all machines. q © 1990 Andreas Stihl, Waiblingen FOREWORD

STIHL 044 2 CONTENTS 9. Electric Handle Heating System 65 9.1 Troubleshooting 65 9.1.1 Troubleshooting Chart 67 9.1.2 Test Connections and Test Values 68 9.2 Switch 69 9.3 Heating Element in Rear Handle 70 9.4 Heating Element in Front Handle 71 9.5 Generator 72 9.5.1 Removal 72 9.5.2 Installation 72 10. Chain Lubrication 74 10.1 Pickup Body 74 10.2 Suction Hose 75 10.3 Vent Valve 75 10.4 Removal and Installa- tion of Oil Pump 75 10.5 Servicing the Oil Pump 76 11. Fuel System 77 11.1 Air Filter 77 11.2 Removal and Installa- tion of Carburetor 78 11.3 Leakage Testing the Carburetor 79 11.4 Servicing the Carburetor 80 11.5 Carburetor Adjustment 84 11.6 Tank Vent 86 11.7 Fuel Filter and Fuel Hose 86 11.8 Tank Housing 88 11.8.1 Removal and Installa- tion 88 12. Special Servicing Tools and Aids 91 12.1 Special Servicing Tools 91 12.2 Servicing Aids 92 4.6 Crankcase 31 4.6.1 Removing the Crankshaft 31 4.6.2 Installing the Crankshaft 36 4.7 Leakage Testing the Crankcase 42 4.7.1 Preparations 43 4.7.2 Pressure Test 44 4.7.3 Vacuum Test 45 4.8 Replacing the Oil Seals 46 5. Ignition System 48 5.1 Repairing Component Parts 48 5.1.1 Spark Plug 48 5.1.2 Spark Plug Terminal 50 5.1.3 Ignition Lead 51 5.1.4 Wiring Harness 51 5.1.5 Stop Switch 53 5.1.6 Ignition Module 54 5.1.6.1 Ignition Timing 54 5.1.6.2 Removing and Installing 54 5.1.7 Flywheel 55 6. Rewind Starter 57 6.1 Routine Maintenance 57 6.2 Rope Rotor/Pawls 57 6.3 Replacing Starter Rope 58 6.4 Replacing Rewind Spring 58 6.5 Tensioning Rewind Spring 59 6.6 Replacing Starter Rope Guide Bush 60 7. AV Handle System 61 7.1 Repair 61 8. Master Control 62 8.1 Removing and Installing 62 8.2 Throttle Trigger/ Interlock Lever 63 1. Specifications 3 1.1 Engine 3 1.2 Fuel System 3 1.3 Ignition System 4 1.4 Cutting Attachment 5 1.5 Weights 5 1.6 Tightening Torques 6 1.7 Special Accessories 7 1.7.1 For User 7 1.7.2 For Service Shop 7 2. Troubleshooting Charts 8 2.1 Clutch, Chain Drive, Chain Brake and Chain Tensioner 8 2.2 Engine 9 2.3 Ignition System 9 2.4 Rewind Starter 11 2.5 Chain Lubrication 12 2.6 Fuel System 13 3. Clutch, Chain Drive, Chain Brake and Chain Tensioner 15 3.1 Clutch Drum/Chain Sprocket 15 3.2 Clutch 16 3.3 Chain Brake 18 3.3.1 Disassembly 18 3.3.2 Assembly 20 3.4 Chain Tensioner 22 4. Engine 23 4.1 Removing and Refitting Exhaust Muffler (also with Catalytic Converter) 23 4.2 Catalytic Converter 23 4.2.1 Construction and Function 23 4.3 Exposing the Cylinder 24 4.4 Cylinder and Piston 25 4.4.1 Removal 25 4.4.2 Installation 26 4.5 Piston Rings 30

STIHL 044 3 1. SPECIFICATIONS 1.1 Engine STIHL single-cylinder two-stroke engine Displacement: Bore: Stroke: Power output: Max. torque: Cylinder bore: Max. permissible engine speed with chain and Rollomatic bar: Clutch engages at: Mean idle speed: Crankshaft: Crankshaft bearings: Crankpin diameter: Bigend bearing: Piston pin dia.: Small-end bearing: Conrod length: Rewind starter: Starter rope: Clutch: Crankcase leakage test at gauge pressure: under vacuum: 70.7 cm 3 (4.3 cu.in) 50 mm (1.97 in) 36 mm (1.42 in) 3.8 kW (5.2 bhp) at 9,500 rpm 4.4 Nm (3.2 Ib.ft) at 6,500 rpm Impregnated for high wear resistance 14,000 rpm approx. 3,400 rpm 2,700 rpm Two-part, drop forged 2 deep groove ball bearings 14.4 mm (0.57 in) Needle cage 10 mm (0.39 in) Needle cage 62 mm (2.44 in) Pawl engagement (2 pawls) with automatic starter rope rewind mechanism 3.5 mm (0.14 in) dia. x 960 mm (37.8 in) Centrifugal clutch without linings, 76 mm (3.0 in) dia. 0.5 bar (7.25 psi) 0.5 bar (7.25 psi) All position diaphragm carburetor with integral fuel pump ack off approx. 1 turn Back off approx. 1 turn (Basic setting with screws initially tight against their seats) 0.8 bar (11.5 psi) Carburetor: Basic setting High speed adjusting screw H: Low speed adjusting screw L: Carburetor leakage test at gauge pressure: 1.2 Fuel System

STIHL 044 4 Fuel tank capacity: Octane number: Fuel mixture: Mix ratio: Air filter: Type: Air gap: Ignition timing: Advance angle: Ignition module: Spark plug (suppressed): Electrode gap: Spark plug thread: Length of thread: Heat range: 0.8 I (27 fl.oz) min. 90 RON Regular brand-name gasoline and brandname two-stroke engine oil 50:1 with STIHL 50:1 two-stroke engine oil; 40:1 with STIHL 40:1 two-stroke engine oil; 25:1 with other branded two-stroke, air-cooled engine oils Prefilter and bisectional box filter Special accessory: Heavy-duty (HD) air filter Transistorized (breakerless) magneto ignition with trigger unit integrated in ignition module 0.15-0.3 mm (0.006-0.012 in) 2.0-3.0 mm (0.08-0.12 in) B.T.D.C. at 8,000 rpm 24.5-29.5° B.T.D.C. at 8,000 rpm Coil winding resistances Primary: Secondary: 0.7...1.0 Ω 7.7...10.3 kΩ Bosch WSR 6 F or NGK BPMR 7 A 0.5 mm (0.020 in) M14 x 1.25 9.5 mm (0.37 in) 200 1.3 Ignition System

STIHL 044 5 1.4 Cutting Attachment Guide bars: Bar tail: Bar lengths: Oilomatic chain: Chain sprockets: Chain speed: Chain lubrication: Oil delivery rate: Oil tank capacity: STIHL Rollomatic guide bars with sprocket nose STIHL Duromatic guide bars with stellite-stipped nose Both types with corrosion- resistant finish and induction hardened rails 3003 Rollomatic: 37, 40, 45 and 50 cm (14, 16, 18 and 20 in) Rollomatic S: 40, 45, 50, 63 and 75 cm (16, 18, 20, 25 and 30 in) Duromatic: 40, 45, 50, 63 and 75 cm (16, 18, 20, 25 and 30 in) 3/8" (9.32 mm) Rapid-Micro and Rapid-Super 3/8" (9.32 mm) Topic-Micro and Topic-Super 7-tooth, 3/8" rim sprocket 7-tooth, 3/8" spur sprocket Options: 8-tooth, 3/8" rim and spur sprockets 20.7 m/s (68 ft/sec) at 9,500 rpm (with 7-tooth, 3/8" sprocket) Fully automatic speed-controlled reciprocating oil pump; no oil feed at idle speed. Additional manual oil flow control (with Economic mark) Adjustable 8 - 18 cm³/min (0.3 - 0.6 fl.oz/min) at 10,000 rpm 0.33 I (0.7 US pt) 1.5 Weights 044 C 6.2 kg (13.6 Ib) 7.6 kg (16.7 lb) 044 W 6.1 kg (13.4 Ib) 7.5 kg (16.5 Ib) 044 5.9 kg (13.0 lb) 7.3 kg (16.1 lb) Dry powerhead without bar and chain: Dry powerhead with 37 cm (15 in) bar and chain:

STIHL 044 6 Remarks 1) 1) 1) 2)3) 4) 4) 2) 1) 1) 1) (Ibf.ft) (8.5) (8.5) (8.1) (6.3) (8.1) (6.6) (24.3) (2.6) (3.0) (37.0) (18.5) (4.0) (4.0) (5.9) (5.9) (0.7) (3.7) (4.4) (4.4) (1.5) (2.2) (2.6) (2.2) (2.2) (3.0) (3.0) (2.2) (17.0) Torque Nm 11.5 11.5 11.0 8.5 11.0 9.0 33.0 3.5 4.0 50.0 25.0 5.5 5.5 8.0 8.0 1.0 5.0 6.0 6.0 2.0 3.0 3.5 3.0 3.0 4.0 4.0 3.0 23.0 For component Crankcase Cylinder Muffler lower casing to cylinder Muffler upper casing (top) Muffler (bottom) Ignition module Crankshaft (ign. end) (flywheel) Carburetor Shroud Carrier (clutch) Spark plug Buffer, top Buffer, bottom Front handle, top Front handle, bottom Handle molding (rear handle) Buffer plate Chain catcher to spiked bumper Spiked bumper to crankcase (top) Generator (heating) Cover of chain tensioner Oil pump Cover of chain brake Brake band Fan housing Hand guard (left) to fan housing Inner side plate Bar mounting Thread size IS-M5x20 IS-M5x20 IS-M5x16 IS-M5x6 IS-M5x16 IS-M5x20 M8x1 M5 IS-M4x16 M12x1 left M14x1.25 IS-P6x26.5 IS-P6x19 IS-P6x19 IS-P6x19 B3.9x19 IS-M4x16 IS-M5x16 IS-M5x12 M3.5x12 M4x8 IS-M4x12 IS-M4x12 IS-M4x 12 IS-M4x16 IS-M4x16 M4x8 M8x21.5 Fastener Spline screw Spline screw Spline screw Spline screw Spline screw Spline screw Nut Nut Spline screw Spline screw Spline screw Spline screw Spline screw Self-tap screw Spline screw Spline screw Spline screw Pan head screw Pan head screw Spline screw Spline screw Spline screw Spline screw Spline screw Pan head screw Collar stud Remarks: 1) Screw must be secured with adhesive 0786 111 1109 (Loctite 270) 2) Screw must be secured with adhesive 0786 111 1101 (Loctite 242) 3) A washer must be fitted under the screw head 4) Screw must be secured with adhesive 0786 111 1117 (Loctite 648) Note: Screws secured with adhesive are easier to release if the adhesive is heated first with a hot air blower (hair dryer). Exercise caution on polymer components. 1.6 Tightening Torques

STIHL 044 7 1128 900 5000 1128 007 1000 1128 007 1001 1128 640 2000 1110 353 1600 0000 792 9150 1128 007 1050 1128 007 1065 STIHL repair kit 044 3/8", 7-tooth rim sprocket kit* 3/8", 8-tooth rim sprocket kit* 3/8", 7-tooth spur sprocket* 3/8", 8-tooth spur sprocket Valve (for fuel tank vent) Chain scabbard extension Gasket set 044 Carburetor parts kit 1.7 Special Accessories 1.7.1 For user 1.7.2 For service * Part may be standard equipment

STIHL 044 8 Remedy Readjust at idle speed adjustment screw (counterclockwise) Fit new springs) Replace all clutch springs Fit new needle cage Fit new retainer Fit new clutch Tension chain as specified Tension chain as specified Check chain lubrication and rectify problem Fit new sprocket Fit new brake spring Fit new brake band 2. TROUBLESHOOTING CHARTS 2.1 Clutch, Chain Drive, Chain Brake and Chain Tensioner Cause Engine idle speed too high Spring hooks) broken Springs stretched or fatigued Needle cage damaged Clutch shoe retainer broken Clutch shoes and carrier worn Chain not properly tensioned Chain not properly tensioned Poor chain lubrication Worn chain sprocket Brake spring broken Brake band stretched or broken Condition Saw chain turns at idle speed Loud noises Chain sprocket wears rapidly Chain wears rapidly Chain does not stop immediately when chain brake is activated

STIHL 044 9 2.2 Engine Always check and, if necessary, repair the following parts before looking for faults on the engine: - Air filter - Fuel system - Carburetor - Ignition system Condition Engine does not start easily, stalls at idle speed, but operates normally at full throttle Engine does not deliver full power or runs erratically Engine overheating Cause Oil seals in crankcase leaking Manifold leaking Cylinder base gasket leaking Crankcase damaged (cracks) Secondary air seepage through poorly mounted or faulty manifold Piston rings leaking or broken Muffler carbonized Insufficient cylinder cooling. Air inlets in fan housing blocked or cooling fins on cylinder very dirty Intake air preheating being used at too high an outside temperature Remedy Replace oil seals Seal or replace manifold Replace gasket Replace crankcase Mount manifold correctly or replace Fit new piston rings Clean muffler (inlet and exhaust), replace spark arrestor screen (if fitted) Thoroughly clean all cooling air openings Remove intake air preheating components; close rotary shutter

STIHL 044 10 2.3 Ignition System Warning: Exercise extreme caution while carrying out maintenance and repair work on the ignition system. The high voltages which occur can cause serious or fatal accidents! Ignition system in order. Look for fault in fuel system and carburetor. yes Replace ignition module. Does engine now run after positive spark test? Fit new flywheel. Is spark test positive? Use ohmmeter to check ignition lead for break. If break is detected, replace ignition lead. Does spark test now produce sparkover? Does flywheel appear to be in good condition? Fit new spark plug. Is air gap correct? Correct the air gap (0.15 - 0.3 mm). Is spark test positive? Insert screwdriver in place of spark plug in spark plug terminal and hold about 4 mm (1/8") away from ground. Sparkover? Replace faulty ignition lead of short circuit wire. Repair contact spring or switch shaft. Faulty insulation on ignition lead or short circuit wire? Is connector sleeve touching short circuit contact? Clean spark plug and reset electrode gap. Does spark test produce powerful spark? Press terminal firmly onto spark plug and fit spring if necessary. Spark plug terminal firmly seated on spark plug? Remove spark plug. Is it in good condition? no no no no no yes no no yes yes no no no no yes yes

Stihl 044 Chainsaw Workshop Mnaual

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