STIHL 045 & 056 CHAIN SAWS Full Service & Repair Manual

~ •• .~ ~ 4) SERVICE MANUAL STIHL 045,056 FOREWORD This Service Manual covers model 045 chain saws up to machine number 5 919 430 as well as later machines unless technical information bulletins have been issued in the meantime with updated repair procedures. Model 045 have substantially the same constructional features as model 056 chain saws. This Service Manual can therefore be used for the 056 chain saws as well. In the event of faults it is quite pos- sible that a single fault may have several causes. It is therefore ad- visable to consult the "Trouble- shooting Chart" in each chapter when tracing faults. We also recommend that you make use of the exploded views in the illustrated parts lists when carrying out repair work. This service manual and all technical information bulletins are intended ex- clusively for the use of STI HL servicing dealers and staff and must not be passed on to third parties. Andreas Stihl Postfach 1760 D-7050 Waiblingen CONTENTS Specifications Saw Chain Drive with Clutch Saw chain drive with clutch, trouble shooting, disassembly and repair Driving Parts Crankshaft with connecting rod, cylinder and piston, exposing the cylinder, removing cylinder and piston, crankshaft and crankcase pressure testing Ignition System Flywheel Magneto Function, spark plug, high tension lead, short-circuit wire and stop switch, checking and adjusting the ignition timing, flywheel, stator plate, ex- changing the breaker point set, ignition coil, condenser, trouble shooting Ignition System Electronic Ignition Advantages and function, con- trolling the function of the electronic system on the motor- checking and adjusting the ignition timing - removal of trigger plate - repair of the electronic - trouble shooting Rewind Starter Design and operation - disassembly and repair - installation of a new starter rope - installation of rewind spring - 2 tensioning the rewind spring - general repair 5 AV-Handle System Disassembly and repair Oil Pump 8 Operation - oil quantity control-removal of oil pump - repair Carburetor set-up and Air Filter Design and operation - disassembly of carburetor and elbow connector - repairing 16 component parts - carburetor adjustment - pressure testing Fuel Tank and Fuel Feed Throttle Control Special Tools 28 32 1 35 36' 38 44 45 46

2 SPECIFICATIONS 045 We reserve the right to change design if this is deemed advan- tageous or necessary. 4.94 cu. in (81 cm3) 2.0" (52 mm) 1.52" (38 mm) 0.76 9.5 :1 48.6 Nm at 5500 r.p.m. 11000 r.p.m. 1800 r.p.m. Grooved ball bearing; bearing driving side with integrated sealing ring Split and two part o 16 mm (0.630Jl) in diameter o 13 mm (0.512") in diameter 70 mm (2.756") distances between axes Forced engagement with automatic rewind of starter rope. Easy starting by starting throttle lock o 4.5x1000 mm (0.177x9.370") in diameter Heavy-duty centrifugal clutch with pressed-on friction linings, 78 mm (3.071") in diameter abt. 2500 r.p.m. Testing pressure 0.5 bar (7.1Ibf./in2) Starter rope: Rewind starter: Clutch starting to engage at: Pressure test of crankcase: Clutch: Crankshaft: Crankpin: Piston pin: Length of conrod: STIHL-one-cylinder two-cycle engine with heavy-chromium plated cylinder wall Piston displacement: Cylinder bore: Piston stroke: Stroke-bore-ratio: Compression: Max torque: Max. allowed speed: Mean idle speed: Bearings: Engine Fuel System Carburetor: Venturi: High speed adjustment screw H: Low speed adjustment screw L: Press.ure test of carburetor: Fuel tank capacity: All position Tillotson diaphragm carburetor HS with integral fuel pump 17.6 mm (0.693") in diameter 11/4turns open 1 turn open 0.4 bar (0.57 Ibf./in2) 0.821- 820 cm3 (1.73 pt)

1) . .- ~J Fuel mixture: Air filter: 3 Regular grade gasoline and branded two-cycle engine oil 1:40 with STIHL two-cycle engine oil 1:25 with other branded two-cycle engine oils Amply dimensioned wire mesh filter Advanced ignition angle: Breaker point gap: Condenser: Ignition System 045 AV Ignition System 045 AVE/AVEQ Bosch flywheel magneto, fully enclosed Magneto edge gap: 6 9 mm (0.24 ... 0.35 in) Advanced ignition: 2.5 2.7 mm (0.098 ... 0.106") before top dead center 26.2 ... 27.50 before top dead center 0.35 ... 0.4 mm (0.014 0.016 in) Capacity about 0.15 0.19 fLF Magneto high tension condenser ignition system (capacitor discharge) without breaker points, water- and dirtproof. Advanced ignition: 2.5 ... 2.7 mm (0.098 ... 0.106") before top dead center Advanced ignition angle: 26.2 ... 27S before top d~ad center Spark plug: Bosch WSR 6 F ~ .-/ Torques for Screws and Nuts Armature air gap: Crankshaft nut Magneto side M 10x1: Crankshaft nut Clutch side M 12x1.5 -Iefthand: Clutch carrier M 12x1.5 -Iefthand: Cylinder head screws M 6x25: Spark plug: Heat range 175 Electrode gap 0.5 mm (0.02 in) Spark plug thread M 14x1.25 Length of thread 9.5 mm (0.37 in) 0.2 ... 0.3 mm (0.007. .. 0.011 in) 30 Nm (21.70 ftllbf.) 35 Nm (25.32 ft/lbf.) 50 Nm (36.165 ftllbf.) 10 Nm (7.233 ft/lbf.) 30 Nm (21.70 ftllbf.)

4 Cutting Attachment Guide bars: Bar lengths: Oilomatic-chains: Chain speed: Chain lubrication: Maximum oil output: Minimum oil output: Mean oil output: Oil tank capacity: Chain sprocket: STIHL Duromatic bar with carbide tipped nose; STIHL Rollomatic bar with spider nose. Either type is protected from corrosion by induction-hardened contact surfaces Duromatic 40, 45, 50 and 63 cm (16, 18, 20 and 25") Rollomatic 37, 40, 45, 50 and 63 cm (15,16, 18, 20 and 25") 9.32 mm (3fa")-Rapid and -Topic 10.26 mm (0.404")-Rapid 17.4 m/sec. (57.1ft per second) at 8000 r.p.m. with 3/8" chain 19.2 m/sec. (63 ft per second) at 8000 r.p.m. with 0.404" chain Fully automatic oil pump with pump plunger, output depending on chain speed, pump supplying oil only when chain is running, additional quantity control by adjusting control bolt. 15 cm3/min. (0.92 cu. in per minute) at 6000 r.p.m. 8.5 cm3/min. (0.52 cu. in per minute) at 6000 r.p.m. 12 cm3/min. (0.73 cu. in per minute) at 6000 r.p.m. 0.36 I = 360 cm3 (0.76 pt) 7 teeth Weights Motor dry without bar and chain: with 37 cm (15") bar and chain: AViAVE: 7.9 kg (17.4 Ib) 9.1 kg (20.1Ib) AVEQ: 8.3 kg (18.3 Ib) 9.5 kg (20.9 Ib) Extras STIHL repair kit (set of the most common wearing parts) for friction shoe rewind starter 1115 900 5000 for single pawl rewind starter 1115 900 5001 Set of gaskets 1115 007 1050

e SAW CHAIN DRIVE AND CLUTCH ~ ~ The power from the engine is trans- mitted to the saw chain by a centrifugal clutch. This clutch is composed of clutch carrier, clutch shoes and clutch springs. But the two washers in front of and behind the clutch as well as the chain sprocket with clutch drum riveted onto it are also needed for a proper operation of the clutch. With increasing speed the clutch shoes, held by the clutch springs, Troubles Bad engagement, clutch slips, chain does not rotate are forced to the outside; they are pressed against the clutch drum which is connected with the chain sprocket thus transmitting the engine power to the chain sprocket and the saw chain. The clutch springs have a certain pre-tension so that clutch will not engage before the engine speed of about 2500 r.p.m. is reached. The carburetor has to be adjusted in such a way (see paragraph carbure- Causes Clutch linings worn 5 tor adjustment) that the chain does not rotate at idle speed. The clutch of the STIHL 045 AV and 045 AV electronic needs almost no maintenance at all but, of course, normal wear cannot be avoided. Therefore, the clutch and the chain sprocket must be checked on proper condition periodically. How to correct Replace the complete set of clutch shoes Clutch and chain sprocket dirty (oil) Wash in clean gasoline, roughen clutch linings with emery cloth ~ ;.// Saw chain does not stop running when idling, extraneous noises No chain lubrication Extreme chain wear Engine speed too high when idling Spring stretched or fatigued Spring hooks damaged Needle cage damaged Drive pin of cover plate broken Worn chain sprocket Readjust idle adjustment screw Replace all springs Replace needle cage Install new cover plate Replace chain sprocket

6 Disassembly and Repair Locking screw A dirty or improperly operating clutch must be disassembled and repaired. For disassembly first loosen the two hex. nuts with which the chain sprocket cover is fastened and remove chain sprocket cover from bar studs. Take off saw chain from chain sprocket and remove with guide bar. Pull off spark plug terminal and unscrew spark plug with combination wrench, screw crankshaft locking screw 11071911200 into spark plug thread and tighten it by hand. This will properly lock the crankshaft. Note: Hexagonal nut and clutch have left-hand thread. Therefore, unscrew by turning them clockwise. Put combination wrench on hex. nut and screw clockwise till piston rests Top: Loosening the crankshaft nut Bottom: Chain sprocket, ciutch with carrier, clutch shoes and clutch springs against the crankshaft locking screw. Loosen and unscrew hex. nut. To guide the clutch shoes on the clutch carrier the clutch is equipped on both sides with a washer. The washers are indented in their center and must be installed in such a way that they are resting with the recess against the carrier. The front washer is of larger diameter to better pro- tect the clutch against saw dust. Top: Clutch wrench Bottom: Loosening the ciutch To disassemble clutch take off front washer. Screw off clutch with wrench 11118931300 clockwise. Thereafter remove second retaining washer, chain sprocket, needle cage and cover plate from crankshaft. The drive pin pressed into the cover plate extending into a boring in the

~ .~ Torque wrench with insert Top: Disassembly of clutch and sprocket cover Bottom: Tightening the crankshaft nut 7 ~ ;;/ chain sprocket and into the small spur g~ar is driving the oil pump at engaged clutch. Replace damaged parts of the clutch; only complete sets of clutch shoes and clutch springs should bE: replaced! If clutch is only fouled all parts must be washed in clean gasoline and then cleaned with com- pressed air. Roughen surfaces of clutch linings with emery cloth. Clean the dirty inside of the clutch drum with a clean, dry rag. The stress to the chain sprocket is especially tough. If it shows visible wear at the teeth it has to be ex- .changed. This wear should not ex- ceed a depth of 0,5 mm (0.019"). A worn chain sprocket reduces the life of the saw chain. If the cover plate too is not in proper condition it has to be replaced as well. To reassemble the clutch place cover plate onto crankshaft so that driving pin extends into the boring of the small spur gear of the oil pump. Then put greased needle cage, chain sprocket and the washer which is smaller in diameter (ob- serve correct inserting position) back into place. Screw in clutch with wrench anti-clockwise and tighten with 5 kpm (36.165 ft/lbf.). Then put front washer which is larger in diameter onto crankshaft. Screw in hex. nut and tighten with torque wrench at 3,5 kpm (25,281 ft/lbf.). Finally insert spark plug.

8 DRIVING PARTS Crankshaft with connecting rod, cylinder and piston Disassembly of fan housing cover Exposing the Cylinder Top: Loosening the slotted nuts of the air filter Bottom: Loosening the hex. nuts Top and bottom: Removing the cover The STIHL 045 AV and 045 AV electronic saws are driven by an air- cooled one-cylinder two-cycle engine. The split two part crankshaft is supported in the crankcase made of electron die cast metal (magne- sium alloy). Crankshaft and connecting rod are drop forged. The crankshaft is rigidly pressed together when needle cage and connecting rod are installed. Cylinder and piston are made of a special alumi- nium alloy. The cylinder wall is heavily chromium impregnated. Take off chain sprocket cover and fan housing cover with rewind starter. Unscrew locking screw of carburetor box cover and cover and remove cover. Loosen two slotted nuts of air filter and pull off filter from the studs. Pry off retaining washers at carburetor from choke shaft and throttle shaft and unhookstarter and throttle rod on carburetor. Unscrew 2 hex. nuts (SW 8) of the carburetor fixation and remove carburetor from studs; to do so pry off impulse hose from nipple at the carbur8tor. Now remove handle frame. To do so unscrew collar screw at the right front side as well as the 2 cyl. hd. screws with inner hex. with which the handle bar is tightened to the handle frame and the 4 cyl. hd. -' ~.

.- ; ,.--/ Top: Loosening the annular buffer Bottom: Pulling off the short circuit wire screws with which the handle frame is screwed onto the carburetor box. Unscrew collar stud next to the oil inspection window with which the carburetor box is fastened through the rubber buffer to the crankcase and unscrew also the annular buffer with which the tank housing is fastened. Pull elbow connector with screw driver from carburetor box and re- Disassembly of fan cover move impulse hose from nipple at the cylinder. Carefully disconnect short circuit wire at the stop switch. Carburetor box with tank housing can now be removed completely. Remove tensioning clamp at cylinder with flat- nose pliers and pull off elbow connector. Unscrew 3 cyl. hd. screws M 4 x 16 of the fan cover fixation and remove fan housing. First, ho- wever, pullout high tension lead of the guidance in the fan cover. Now clean outside of cylinder thoroughly and check for defective- ness. 9 Disassembly of Cylinder and Piston Screwed in locking screw Before unscrewing cylinder remove spark plug and insert locking screw into spark plug port by hand until it fits tight. Thereafter unscrew hex. nut for fastening the flywheel and remove the flywheel with the puller from the crankshaft (see paragraph flywheel). Moreover, disassemble the hex. nut for the fastening of the clutch as well as the clutch from the crankshaft. Should you find out during further disassembly that crankcase or crankshaft happen to be defective the clutch cannot be removed anymore from crankshaft with a taken off cylinder. Thereafter remove locking screw again.

STIHL 045 & 056 CHAIN SAWS Full Service & Repair Manual

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