STIH) STIHL MS 290, 310, 390 2004-11
Contents 1. Introduction 2 2. Safety Precautions 3 3. Specifications 4 3.1 3.1.1 3.2 3.3 3.4 3.5 Engine Engine (USA only) Fuel System Ignition System Chain Lubrication Tightening Torques 4 4 5 5 5 6 6.5 6.5.1 6.5.2 6.6 6.7 30 31 33 35 35 7. Ignition System 36 7.1 7.1.1 7.1.2 Ignition Module Ignition Timing Removing and Installing Testing the Ignition Module Spark Plug Boot Ignition Lead Flywheel Contact Spring Replacing Wiring Harness Ignition System Troubleshooting 37 37 7.1.3 4. 4.
1. Introduction This service manual contains detailed descriptions of all the typical repair and servicing procedures for this power tool. As the design concept of models MS 290, MS 310 and MS 390 is almost identical, the descriptions and servicing procedures in this manual generally apply to all three models. Differences are described in detail. The special tools mentioned in the descriptions are listed in chapter "Special Servicing Tools" of this manual.
2. Safety Precautions If the engine is started up in the course of repairs or maintenance work, observe all local and countryspecific safety regulations as well as the safety precautions and warnings in the instruction manual. Gasoline is an extremely flammable fuel and can be explosive in certain conditions. Improper handling may result in burns or other serious injuries. Warning! Do not bring any fire, flame, spark or other source of heat near the fuel.
3. 3.1 Specifications Engine Displacement: Bore: Stroke: Engine power to ISO 7293: Max. permissible engine speed with bar and chain: Idle speed: Clutch: Clutch engages at: Crankcase leakage test at gauge pressure: under vacuum: 3.1.1 MS 310 MS 390 56.5 cm3 46 mm 34 mm 3.0 kW (4.1 bhp) at 9,500 rpm 59.0 cm3 47 mm 34 mm 3.2 kW (4.4 bhp) at 9,500 rpm 64.1 cm3 49 mm 34 mm 3.4 kW (4.6 bhp) at 9,500 rpm 12,500 rpm 13,000 rpm 2,800 rpm Centrifugal clutch without linings 3,500 rpm 13,000 rpm 0.5 bar 0.
3.2 Fuel System Carburetor leakage test at gauge pressure: Operation of tank vent at gauge pressure: Fuel: 3.3 0.3 bar (4.35 psi) as specified in instruction manual Ignition System Air gap between ignition module and fanwheel: Spark plug (suppressed): Electrode gap: 3.4 0.8 bar (11.60 psi) 0.15 – 0.3 mm Bosch WSR 6F NGK BPMR 7 A 0.
3.5 Tightening Torques DG screws are used in polymer and light metal components. These screws form a permanent thread when they are installed for the first time. They can be removed and installed as often as necessary without impairing the strength of the screwed assembly, providing the specified tightening torque is observed. For this reason it is essential to use a torque wrench.
4. 4.
4.2 Rewind Starter Condition Cause Remedy Starter rope broken Rope pulled out too vigorously as far as stop or over edge, i.e.
4.3 Chain Lubrication In the event of trouble with the chain lubrication system, check and rectify other sources of faults before disassembling the oil pump.
4.4 Ignition System Warning! Exercise extreme caution while carrying out maintenance and repair work on the ignition system.
4.5 Carburetor Condition Cause Remedy Carburetor floods; engine stalls Inlet needle not sealing.
Condition Cause Remedy Engine will not idle, idle speed too high Throttle shutter opened too wide by idle speed screw (LA) Reset idle speed screw (LA) correctly Engine leaking Seal the engine Idle jet bores or ports blocked Clean jet bores and ports and blow clear with compressed air Idle jet too rich or too lean Set low speed screw (L) correctly Setting of idle speed (LA) incorrect – throttle shutter completely closed Set idle speed screw (LA) correctly Small plastic plate in valve jet does n
4.
5. 5.1 Clutch, Chain Drive, Chain Brake and Chain Tensioner Clutch Drum/Chain Sprocket 209RA000 VA 143RA007 VA If there are signs of serious wear on the inside diameter of the clutch drum (1), check the remaining wall thickness. If it is less than about 80% of the original thickness, fit a new clutch drum. If the clutch drum has to be replaced, also check the brake band, b 5.6.2 : Remove the needle cage. – Remove the chain sprocket cover.
5.2 Chain Catcher 5.3 Spiked Bumper – Rotate clutch drum/chain sprocket and apply slight pressure at the same time until the oil pump drive spring engages the notch. 2 209RA193 VA Install all other parts in the reverse sequence. 1 1 209RA003 VA – Fit rim sprocket with the cavities facing outwards. – Remove the chain sprocket cover, bar and chain. – Remove the chain sprocket cover, bar and chain. : Take out the screw (1). – Take out the screws (arrows). : Remove the chain catcher (2).
5.4 Collar Stud 5.5 1 – Install the collar stud with the M 8 stud puller, b 12. – Tighten down the collar stud firmly, b 3.5 – Troubleshooting – b 4.1 – Remove the clutch drum/chain sprocket, b 5.1 – Remove the prefilter, b 11.1 209RA099 VA Install all other parts in the reverse sequence. Clutch – Remove the chain sprocket cover with cutting attachment. : Use M 8 stud puller 5910 893 0501, b 12, to remove the collar stud (1).
: Unscrew the clutch from the crankshaft in the direction of the arrow (left-hand thread). 146RA206 VA 209RA007 VA 209RA006 VA f : Carefully clamp the clutch in a vise. : Pull the retainers off the clutch shoes. 2 1 146RA207 VA – Clean all parts in a little standard solvent-based degreasant containing no chlorinated or halogenated hydrocarbons, b 13. : Attach one end of each spring (1) to the clutch shoes.
5.6 5.6.1 TOP 209RA010 VA 1 : Push cover washer (1), "TOP" (arrow) facing outward, onto the crankshaft. Chain Brake Checking Operation The chain brake is one of the most important safety devices on the chainsaw. Its efficiency is measured in terms of the chain braking time, i.e. the time that elapses between activating the brake and the saw chain coming to a complete standstill. The shorter the braking time, the better the efficiency and protection offered against being injured by the rotating chain.
: Remove the brake spring (1) from the bell crank (2). – Install a new brake band if there are noticeable signs of wear (large areas on inside diameter and/or parts of outside diameter) and its remaining thickness is less than 0.6 mm. Thickness of brake band must not be less at any point. 1 135RA029 VA 2 209RA194 VA 209RA 013 VA 1 : Remove the E-clip (arrow). 2 1 209RA014 VA 135RA030 VA : If the brake band is still serviceable, use No. 120 emery paper or emery cloth (grain size approx.
– Lubricate all sliding and bearing points with STIHL multipurpose grease or, preferably, molybdenum grease (e.g. Molykote), b 13. 3 1 2 208RA004 VA 135RA032 VA 1 2 : Carefully pry the hand guard (1) and bell crank (2) off their pivot pins and remove them together. : Fit the bushing (1) in the hand guard (2). : Insert M5x24 screw (3) and tighten it down firmly, b 3.5 – Pull the bell crank out of the hand guard. Install all other parts in the reverse sequence.
5.7 5.7.1 Replacing Pins Removing 209RA185 VA Brake spring anchor pin 209RA188 VA Drive out the pin in the direction of the arrow so as not to damage the annular bead which was formed in the engine housing bore when the pin was originally installed. The new anchor pin will not otherwise fit properly and the brake spring will not be held securely. 209RA190 VA If the groove of the anchor pin is worn, install a new pin. Hand guard pivot pin Cam lever pivot pin – Remove the hand guard, b 5.6.
5.7.2 Installing – Before installation, coat the knurled area of the new pin with Loctite 243, b 13. – Carefully tap home the pin squarely from the outside inwards, in direction of cylinder. 1 209RA208 VA – Position the new pin in the bore so that the knurling on the pin meshes with the existing knurling in the bore. Turn pin back and forth as necessary. Install all other parts in the reverse sequence. a Spring anchor pin : Drive home pin (1) until dimension “a” is 3.0 ± 0.
5.8 Chain Tensioner 6. 6.1 Engine Muffler/Spark Arresting Screen This machine does not have a conventional crankcase. The engine consists of the cylinder, piston, crankshaft and engine pan. 135RA046 VA 135RA044 VA – Troubleshooting, b 4.6 : Pull the spur gear out of the cover. – Remove the chain sprocket cover. : Take out the screw (arrow). – Pull tensioner assembly out of the engine housing. 2 3 135RA047 VA : Take the thrust pad (1) off the adjusting screw (2).
1 2 : Remove spark arresting screen (1), if fitted. Clean the screen or fit a new one if necessary : Remove the screws (arrows) sideways from the flange. Remove screw (1) as follows: : Remove the muffler (2). – Remove the shroud, b 6.4 2 209RA199 VA 209RA025 VA 3 209RA022 VA 1 1 : Install the muffler (1), making sure the conical spring washers (2) are fitted correctly as shown. : Use new nuts (3) and tighten them down firmly, b 3.5. – Remove the screw sideways from the flange.
This makes adjustment of the prescribed idle speed difficult, if not impossible. Moreover, the transition from idle speed to part or full throttle is not smooth. The engine housing can be checked thoroughly for leaks with the carburetor and crankcase tester and the vacuum pump, b 11.2.2 Preparations 1 1 2 3 176RA017 VA Defective oil seals and gaskets or cracks in castings are the usual causes of leaks. Such faults allow supplementary air to enter the engine and upset the fuel-air mixture. 6.2.
6.2.2 Pressure Test 6.2.3 209RA029 VA – Continue with vacuum test, b 6.2.3 Vacuum Test Oil seals tend to fail when subjected to a vacuum, i.e. the sealing lip lifts away from the crankshaft during the piston's induction stroke because there is no internal counterpressure. A test can be carried out with the vacuum pump to detect this kind of fault. – Carry out pressure test, b 6.2.2 – Carry out preparations, b 6.2.1 : Connect pressure hose to nipple (arrow) on test flange.
6.3 Oil Seals If the vacuum reading remains constant, or rises to no more than 0.3 bar within 20 seconds, it can be assumed that the oil seals are in good condition. However, if the pressure continues to rise (reduced vacuum in the crankcase), the oil seals must be replaced. It is not necessary to disassemble the complete engine if only the oil seals have to be replaced. – After finishing the test, open the vent screw and disconnect the hose. – Remove the oil pump, b 10.4.
Z 1 2 1 : Push the installing sleeve (1) 1122 893 4600 on to the crankshaft stub. Ignition side – Remove the flywheel, b 7.3 : Apply puller (1) 5910 890 4400 with No. 3.1 jaws 0000 893 3706. – Clamp the puller arms. – Pull out the oil seal. Take care not to damage the crankshaft stub. 209RA088 VA 1 : Use press sleeve (1) 1127 893 2400 to install the “soft” oil seal. – Wait about one minute, then rotate the crankshaft. – Install the oil pump, b 10.4.1 Install all other parts in the reverse sequence.
6.4 Shroud 1 2 2 3 1 : Use press sleeve (1) 1127 893 2400 to install the “soft” oil seal. 209RA192 VA 209RA109 VA 209RA090 VA 1 : Pull off the spark plug boot (1). Machines up to 2001 : Pull the ignition lead (3) out of the retainer (2) and guides (arrows). : Push the tank vent (1) into its seat (arrow) in the shroud (2). – Wait about one minute, then rotate the crankshaft. – Install the flywheel, b 7.3 Install all other parts in the reverse sequence.
6.5 Removing and Installing the Engine Always check and, if necessary, repair the fuel system, carburetor, air filter and ignition system before looking for faults on the engine. 1 209RA093 VA – Remove the shroud, b 6.4 – Remove the oil pump, b 10.4.1 209RA100 VA – Remove the handle housing, b 9.2 – Remove the muffler, b 6.1 – Set piston to bottom dead center. – Unscrew the collar stud, b 5.4 – Remove the flywheel, b 7.3 : Lift cylinder with crankshaft upwards and off the engine pan.
6.5.1 Cylinder – Lubricate piston and piston rings with oil. 1 209RA096 VA 209RA095 VA 2 : Remove the oil seals (2). The cylinder can be removed without having to take the engine pan out of the housing. : Inspect ball bearings (1) and replace if necessary, b 6.7 – Remove the engine, b 6.5 – Inspect the cylinder and crankshaft for damage and replace if necessary. : Lift the crankshaft and pull the piston out of the cylinder at the same time.
– Push the crankshaft home until the ball bearings are seated. Make sure that ball bearings and oil seals are correctly seated. 209RA105 VA 209RA101 VA 1 : Compress the piston rings with clamping strap (1) 1127 893 2602. : Push the manifold on to the intake port so that the straight faces (arrows) are in alignment. : Push the piston carefully into the cylinder. : Remove the clamping strap (1). 30˚ a 2 : Apply a thin bead of sealant to the groove in the engine pan mating face, b 13.
135RA087 VA Piston 135RA085 VA 6.5.2 – Pull the piston out of the cylinder, b 6.5.1 : Inspect piston rings and replace if necessary, b 6.6 : Push the assembly drift, small diameter first, through the piston and small end (needle cage) and line up the piston. : Fit needle cage (arrow) in the connecting rod. : Fit the piston pin (1) on the assembly drift (2) and slide it into the piston (the pin slides home easily if the piston is warm). : Ease the hookless snap rings out of the grooves.
: Remove the sleeve from the tool. 249RA146 VA : Remove the sleeve and slip it onto the other end of the shank. Inner pin must again point toward flat face. 249RA149 VA : Push the large slotted diameter of the sleeve over the magnet and snap ring. Position the sleeve so that the inner pin (1) points toward the flat face (2) of tool's shank.
6.6 Piston Rings 6.7 Crankshaft – Pull the piston out of the cylinder, b 6.5.1 1 2 135RA097 VA 209RA107 VA – Remove rings from the piston. – Remove the piston, b 6.5.2 – Fit the snap rings so that their gaps are on the piston's vertical axis (they must point either up or down – see arrow). : The crankshaft (1) and connecting rod (2) form an inseparable unit. This means the crankshaft must always be replaced as a complete unit. – Install the piston, b 6.5.
7. Ignition System 135RA100 VA 135RA101 VA Exercise extreme caution when troubleshooting and carrying out maintenance or repair work on the ignition system. The high voltages which occur can cause serious or even fatal accidents! : Heat ball bearing to approx. 50°C and, with closed side facing outwards, push it on to the crankshaft stub as far as stop. : Slide oil seals over the crankshaft stubs so that their open sides are facing the ball bearings (arrow).
Ignition Module 7.1.1 1 Ignition Timing Ignition timing is fixed and cannot be adjusted during repair or servicing work 2 Removing and Installing 1 2 3 209RA112 VA Since there is no mechanical wear in these systems, ignition timing cannot get out of adjustment as a result of wear. 7.1.2 209RA109 VA 7.1 The ignition module accommodates all the components required to control ignition timing. There are two electrical connections on the coil body: – Remove the handle housing, b 9.
1 209RA116 VA : Disconnect the short circuit wire (1) and pull it out of the retainer (arrow). : If necessary, pull the retainer (1) out of the ignition module. 2 209RA118 VA 209RA114 VA 1 : Rotate the flywheel until its raised edge (arrow) is in line with the ignition module. Install in the reverse sequence. : Remove the screw (2) with washer. 1 1 – Pull the ignition module downwards. : Fit screw (1) with ground wires but do not tighten down yet. : Push the grommet (1) upwards.
7.1.3 To test the ignition module, use either the ZAT 4 ignition system tester 5910 850 4503 or the ZAT 3 ignition system tester 5910 850 4520. 3 2 : Tighten down the screw (1) firmly, b 3.5 : Make sure the crimp connections of the ground wires (3) are next to one another. : Tighten down the screw (2) firmly, b 3.5 2 The ignition test refers only to a spark test, not to ignition timing.
7.2 Spark Plug Boot 212RA236 VA If a spark is visible, the ignition system is in order. If no spark is visible in the window (2), check the ignition system with the aid of the troubleshooting chart, b 7.6 While using the ZAT 3, hold it only by the handle (4) or position it in a safe place. Keep fingers or other parts of your body at least 1 cm away from the spark window (3), high voltage connection (2), ground connection (5) and the ground terminal (1). Warning! High voltage – risk of electrocution.
7.2.1 Ignition Lead Install all other parts in the reverse sequence. 209RA120 VA 176RA160 VA 1 – Use a pointed tool to pierce the center of the ignition lead’s insulation, about 15 mm from the end of the lead. – Troubleshooting – b 4.4 : Pinch the hook of the leg spring into the center of the lead (arrow). : Pull the grommet (arrow) downwards and off the ignition lead. – Remove the ignition module, b 7.1.2 : Pull the ignition lead (1) upwards and out of the tank housing.
7.3 Flywheel – Remove the fan housing with rewind starter, b 8.2 – Use a suitable tool to tap the end of the puller to release the flywheel. – Use locking strip to block the piston 0000 893 5903, b 5.5 – Degrease crankshaft stub and bore in flywheel with standard solvent-based degreasant containing no chlorinated or halogenated hydrocarbons, b 13. Install in the reverse sequence. 1 : Unscrew the flywheel nut (1).
7.4 Contact Spring 7.5 Replacing Wiring Harness 1 1 – Remove the switch shaft, b 9.4 : Take the short circuit wire (1) out of the guide (arrows) and pull it off the contact spring (2). 209RA131 VA 2 209RA129 VA 2 209RA126 VA 1 : Pull the wiring harness (1) out of the retainer (arrows) in the engine housing. – Remove the handle housing, b 9.2 – Remove the flywheel, b 7.3 – Remove the ignition module, b 7.1.2 – Remove the shroud, b 6.4 1 : Take out the screw (1).
– Install the ignition module, b 7.1.2 1 3 Install all other parts in the reverse sequence. 1 When installing, push grommet (1) sideways into the housing recess (arrows). The wiring harness (2) must be on the right of the ignition lead (3). 209RA136 VA 209RA133 VA 2 : Push additional ground wire (1) into the retainer (arrows). : Position the cable lug against the cylinder with its crimping facing outwards. 209RA134 VA 2 1 : Position the wiring harness (1) under the ignition lead (2).
7.
1 Powerful spark? yes no Check air gap and reset if necessary Check flywheel: – Have pole shoes turned blue? Install new flywheel Disconnect short circuit wire from ignition module Check ignition lead: – Severe chafing? – Spark plug boot: Holes/cracks? – Resistance: spark plug boot to ground: spec. 1.5 – 12kW – Check resistance of ignition lead: spec.
2 3 Check operation of Master Control lever/switch shaft or separate stop switch – Short circuit wire chafed? – Contact gap (contact springs) If necessary, install new ignition lead and/or contact springs Re-connect short circuit wire yes Powerful spark? no Install new ignition module yes Check #"/$ function on Master Control lever/ switch shaft or separate stop switch MS 290, MS 310, MS 390 Engine runs no Look for fault in fuel system or carburetor, check engine for leaks, check position of flyw
If the action of the starter rope becomes very stiff and the rope rewinds very slowly or not completely, it can be assumed that the starter mechanism is in order but plugged with dirt. At very low outside temperatures the lubricating oil on the rewind spring may thicken and cause the spring windings to stick together. This has a detrimental effect on the function of the starter mechanism.
8.4 Rope Rotor 8.5 – Troubleshooting – b 4.2 – Remove the fan housing with rewind starter, b 8.2 – Remove the starter rope/ remaining rope from the rotor – Remove the fan housing, b 8.2 – Remove any remaining rope from the fan housing. Relieving tension of rewind spring Starter Rope/Grip – Install a new starter rope, b 8.
212RA206 VA : Thread the new rope through the top of the starter grip. 209RA145 VA 146RA195 VA : Thread the new rope through the top of the starter grip. – Secure the rope with a simple overhand knot. : Pull the rope back until the knot locates in the rotor’s recess. – Pull the rope with knot into the starter grip. 209RA143 VA 176RA183 VA – Tension the rewind spring, b 8.5.1 ElastoStart starter grip All versions : Pry nipple of starter rope out of the starter grip.
8.5.1 Tensioning – Remove the fan housing with rewind starter, b 8.2 When the starter rope is fully extended, it must still be possible to rotate the rope rotor at least another half turn before maximum spring tension is reached. If this is not the case, pull the rope out, hold the rope rotor steady and take off one turn of the rope. 209RA148 VA – Relieve tension of rewind spring, b 8.4 : Hold the rope rotor steady. : Pull out the rope with the starter grip and straighten it out.
8.6 Starter Rope Guide Bushing 8.7 – Troubleshooting – b 4.2 Wear on the guide bushing is accelerated by the starter rope being pulled sideways. The wall of the bushing eventually wears through and the bushing becomes loose. 209RA151 VA Removing – Remove the rope rotor, b 8.4 – Place the new bushing in the fan housing. The replacement spring comes ready for installation and is secured in a frame. 1 – Remove fan housing with rewind starter, b 8.
9. – Lubricate the spring with a few drops of STIHL special lubricant before installation, b 13. – Position replacement spring with frame in the fan housing. : Position suitable tools on the recesses (arrows) and push the spring into its seat in the fan housing If the rewind spring pops out during installation, fit it in the installing tool 1116 893 4800 as follows: : Fit the rewind spring in the counterclockwise direction, starting from outside and working inwards. : Take out the screws (arrows).
9.2 Handle Housing – Remove the front handle, b 9.1 – Remove the carburetor, b 11.2.1 2 – On machines up to 2002 remove the tank vent, b 11.5.1 – On machines from 2002, remove tank vent valve with hose, b 11.5.2 : Pry bumper strip (1) out of housing. 209RA069 VA 209RA211 VA 1 : Disconnect the short circuit wire from the switch shaft by pulling it to the left and take it out of the retainers (arrows). : Remove the plug (2). 2 1 1 : Take out the screw (1). : Remove the sleeve (1).
209RA071 VA – Remove the switch shaft, b 9.4 : Push the manifold (1) into the handle housing. 1 – Remove the contact spring, b 7.4 209RA075 VA 1 If the handle housing is being replaced because of damage, carry out the following additional operations: 2 – Remove the throttle trigger/ interlock lever, b 9.5 – Replace damaged annular buffers, b 9.3 : Pass the short circuit and ground wires and grommet (1) through the housing opening. Install in the reverse sequence. : Fit the grommet (1).
Annular Buffers 9.3.1 Front Handle/Handle Housing 9.3.2 Rubber anti-vibration buffers are installed between the engine housing, handle housing and front handle. Damaged rubber buffers (annular buffers) must always be replaced in sets. Handle Housing/Engine Housing 1 209RA077 VA Apply STIHL Press Fluid OH 723, b 13, to new annular buffers to simplify installation. 209RA079 VA 9.3 – Remove the front handle, b 9.1 : Pry both annular buffers (arrows) out of the front handle.
9.3.3 Front Handle/Engine Housing 209RA081 VA 209RA083 VA Install all other parts in the reverse sequence. : Push annular buffer into the engine housing until its groove (arrow) engages over the housing rib. – Remove the chain sprocket cover, b 5.1 Install all other parts in the reverse sequence. : Push the annular buffer inwards and remove. – Remove the front handle, b 9.1 Install in the reverse sequence. 209RA082 VA – Coat the new annular buffer with STIHL Press Fluid OH 723, b 13.
– Remove the air filter, b 11.1 : Pull the switch shaft sideways out of the pivot mount and the handle housing. – Move the switch shaft to the “Choke“ position. : Pull the contact sleeve out of the switch shaft to the left. 1 209RA158 VA 2 Check correct installed position of short circuit wire (arrows). Install all other parts in the reverse sequence. Install in the reverse sequence. : Pull the short circuit wire out of the retainers (arrows). 209RA085 VA 209RA156 VA Switch Shaft 209RA069 VA 9.
Throttle Trigger/ Interlock Lever 1 209RA168 VA 209RA166 VA 1 : Pry the throttle rod out of the throttle trigger. – Remove the carburetor box cover, b 11.1 209RA204 VA 9.5 2 : Fit the throttle trigger (1) so that the seat for the throttle rod points upward. : Take out the screw (1). : Use a 4 mm drift to push home the cylindrical pin (1). : Squeeze the lugs (arrows) together, swing the handle molding up and lift it away. 3 : Use a 4 mm drift to drive out the dowel pin (1).
1 Chain Lubrication Pickup Body/Suction Hose Impurities gradually clog the fine pores of the filter with minute particles of dirt. This prevents the oil pump from supplying sufficient oil to the bar and chain. In the event of problems with the oil supply system, first check the oil tank and the pickup body. Clean the oil tank if necessary. 1 209RA176 VA 2 209RA173 VA 10. 10.1 – Troubleshooting – b 4.3 : Press the interlock lever (1) downward. – Unscrew the oil tank cap and drain the oil tank.
10.2 – If necessary, flush out the oil tank. Valve Dispose of cleaning solution properly in accordance with local environmental requirements. Cleaning the valve Install in the reverse sequence. – Drain the oil tank. a – Remove the cutting attachment. Collect chain oil in a clean container. If necessary, dispose of it properly at an approved disposal site. – Observe safety precautions, b 2.
Tank Cap 2 2 1 1 : Remove the sealing ring (1) from the tank cap (2). – Drain the oil tank. Collect chain oil in a clean container. If necessary, dispose of it properly at an approved disposal site. Machines up to 1998 Install in the reverse sequence. 209RA030 VA 3 209RA195 VA 4 10.4 Oil Pump 10.4.1 Removing and Installing 209RA197 VA 10.3 – Remove the clutch, b 5.5 – Remove the worm with drive spring (arrow). Always install a new sealing ring.
10.4.2 Servicing 1 2 32 209RA035 VA 209RA033 VA : Swing the oil pump (1) forwards a little. 7 8 9 : Hold the elbow connector at a slight angle and fit the oil pump. : Carefully remove oil pump (1), pulling the elbow connector (2) off the engine housing nipple at the same time. 209RA036 VA 5 4 2 1 6 Check the suction hose and pickup body are clean before disassembling the oil pump, b 10.1. – Remove the oil pump, b 10.4.
11. 11.1 Fuel System Air Filter Dirty air filters reduce engine power, increase fuel consumption and make starting more difficult. The air filter should be cleaned when there is a noticeable loss of engine power. – Close the choke shutter. 209RA041 VA 209RA037 VA 1 1 : Hold the elbow connector (1) at 90 degrees and push it into the pump. – Remove all loose dirt from around the filter. : Remove the prefilter (1) upwards. – Turn the elbow connector to the right. 1 1 2 Always install new O-rings.
11.2 Carburetor 11.2.1 Removing and Installing – Turn the screwdriver counterclockwise to pry the two halves of the air filter apart. – Repeat the procedure on the other side. 1 2 209RA045 VA 209RA200 VA 1 : Detents (1) must engage audibly in the bushings (2). Install all other parts in the reverse sequence. – Remove the air filter, b 11.1 : Remove the baffle (1) (if fitted). : Insert blade of screwdriver in the slot (arrow) and turn it to separate the two halves of the air filter.
11.2.2 Leakage Test – Troubleshooting – b 4.5 1 In the case of problems with the carburetor or fuel supply system, also check and clean, b 11.5.1 and 11.5.2. 2 209RA047 VA 1 209RA201 VA 3 : Pull the tank vent (1) (if fitted) out of the grommet (2). : Pull the hose (3) off the tank vent (1). : Where applicable, fit baffle(1) with the word ”TOP” (arrow) facing outwards. The carburetor can be tested for leaks with the carburetor and crankcase tester 1106 850 2905. – Remove the carburetor, b 11.2.
11.3 Servicing the Carburetor 11.3.1 Metering Diaphragm 1 : Push the nipple into the pressure hose of tester 1106 850 2905. : Close the vent screw (1) on the rubber bulb (2) and pump air into the carburetor until the pressure gauge (3) shows a reading of approx. 0.8 bar (80 kPa). If this pressure remains constant, the carburetor is airtight. However, if it drops, there are two possible causes: 209RA051 VA 1 212RA159 VA 2 249RA012 VA 3 – Remove the carburetor, b 11.2.
11.3.2 Inlet Needle Install in the reverse sequence. The gasket and metering diaphragm are held in position by integrally cast pegs (2+3). – Fit the end cover. – Fit screws and tighten them down firmly, b 3.5 212RA162 VA The diaphragm material as well as the inlet and outlet valves are subjected to continuous alternating stresses and eventually show signs of fatigue, i.e. the diaphragm distorts and swells and has to be replaced. Install all other parts in the reverse sequence.
11.3.3 Fixed Jet 11.3.4 Pump Diaphragm 1 4 3 1 212RA165 VA 212RA164 VA 2 212RA163 VA 1 – Remove the metering diaphragm, b 11.3.1 – Remove the carburetor, b 11.2.1 : Fit spring (2) in bore. : Use a suitable screwdriver to unscrew the fixed jet (1). : Take out the screw (arrow). : Insert spindle (3) in the inlet control lever (4). Take care not to damage the fixed jet. – Engage clevis in annular groove on head of the inlet needle. Install in the reverse sequence.
1 212RA168 VA The diaphragm material as well as the inlet and outlet valves are subjected to continuous alternating stresses and eventually show signs of fatigue, i.e. the diaphragm distorts and swells and has to be replaced. : Fit the diaphragm and gasket on the carburetor body so that the tabs (arrow) point toward the connector (1). – Place the end cover on the carburetor body. The pump diaphragm, gasket and end cover are held in position by integrally cast pegs.
11.4 Adjusting Carburetor 11.4.1 User Adjustment (Carburetor without Limiter Caps) Engine stops while idling Standard setting (without tachometer) To readjust the carburetor, start with the standard setting. – Carefully screw down both adjusting screws (H and L) until they are against their seats. Then make the following adjustments: – Open high speed screw (H) one full turn. – Open low speed screw (L) one full turn.
11.4.2 User Adjustment (Carburetor with Limiter Caps) Chain runs when engine is idling 209RA053 VA – Open the low speed screw L one quarter of a turn. Standard setting – Open the idle speed screw LA counterclockwise until the chain stops running – then turn the screw another full turn in the same direction. Adjustment for operation at high altitude or at sea level A slight correction of the setting may be necessary if engine power is not satisfactory when operating at high altitude or at sea level.
11.4.3 Basic Setting (Carburetor with Limiter Caps) – Check chain tension. The limiter caps need to be removed from the adjusting screws only if it is necessary to replace the high speed screw (H) or low speed screw (L) or clean the carburetor. – Warm up the engine. 176RA327 VA Carry out the two following steps: After removing the limiter cap it is necessary to carry out the basic setting.
11.5 Tank Vent 11.5.1 Machines up to 2002 Clean all components in standard solvent-based degreasant containing no chlorinated or halogenated hydrocarbons, b 13. In the event of trouble with the carburetor or the fuel supply system, always check and clean the tank vent. Install in the reverse sequence. Check operation by performing vacuum test on the tank via the fuel hose.
11.5.2 Machines from 2002 – Use vacuum pump to subject tank vent valve to vacuum. 2 1 209RA047 VA 3 – Remove the hose. Equalization of pressure in the fuel tank takes place via the tank vent valve. There must be no build-up of vacuum during the test. In the event of a malfunction, install a new tank vent. Clean the hose with compressed air and a little standard solvent-based degreasant containing no chlorinated or halogenated hydrocarbons, b 13.
11.6 Fuel Tank 11.6.1 Pickup Body 11.6.2 Suction Hose The diaphragm pump draws fuel out of the tank and into the carburetor via the fuel hose. Any impurities mixed with the fuel are retained by the pickup body (filter). The fine pores of the filter eventually become clogged with minute particles of dirt. This restricts the passage of fuel and results in fuel starvation. In the event of trouble with the fuel supply system, always check the fuel tank and the pickup body first.
11.6.3 Tank Cap 4 3 11.6.4 Replacing Engine Housing 2 2 1 The fuel tank and engine housing are a single unit. 1 209RA197 VA 209RA195 VA – Drain off oil and fuel and collect in a clean container. If necessary, dispose of properly at an approved disposal site. : Remove the sealing ring (1) from the tank cap (2). – Drain the fuel tank. Collect fuel in a clean container. If necessary, dispose of it properly at an approved disposal site. Install in the reverse sequence.
– Remove the chain catcher, b 5.2 – Remove the annular buffers from the front handle/engine housing, b 9.3.2 – Remove the annular buffer from the handle housing/engine housing, b 9.3.3 – Remove the chain tensioner, b 5.8 – Remove the wiring harness, b 7.5 – Remove engine with engine pan, b 6.5 – Remove the tank caps, b 10.3 and b 11.6.3 Install in the reverse sequence.
12. Special Servicing Tools No. Part Name Part No. Application 1 2 3 4 5 6 7 0000 893 5903 0000 855 8106 1108 893 4800 1127 893 2601 1128 850 4200 5910 890 2800 1106 850 2905 8 Locking strip Sealing plate Wooden assembly block Clamping strap Test flange Hook Carburetor and crankcase tester Vacuum pump 0000 850 3501 9 10 11 12 13 14 15 16 17 18 19 20 21 22 - Nipple - Fuel line Press sleeve Puller - Jaws (No. 3.
No. Part Name Part No. Application Rem.
13. Servicing Aids No. Part Name Part No.
