Transcript Use
Stihl MS 440/044 Chainsaw SECTION: Tools and Equipment ISSUED: 02-2011 REVISED: ##-#### Objectives • To provide an understanding of the following – Specifications – Use – Maintenance – Safety Specifications • STIHL MS 440/044 • 2 stroke engine • 20” Bar • 5.2 horse power • Chain • 50:1 pre mix – 33 cutting teeth – Carbide tipped • HD air filter with pre-filter • Spark plug – Bosch WSR6 F or NGK BPMR 7A • Idle RPM-2,500 • Max RPM-13,500 Use • Vertical ventilation • Forcible entry • Cutting timber and brush • Cutting lumber – Shoring operations Control Lever Positions • Stop • Run • Half choke • Choke Interlock and throttle must be depressed to switch from run to half choke or choke Parts • Chain brake – Manual and inertia operated • Decompression valve – Allows for an easier and quicker start Parts • Chain catch – Reduces risk of operator contact with chain should it break or derail • Chain tensioner – Allows for chain tension adjustment Starting Procedures • Ground starting method – Place saw on ground – Disengage chain break – Ensure control lever is in choke position – Hold handle firmly with left hand Starting Procedures • Place foot firmly in handle • Pull starter grip • Repeat until engine fires • Adjust control lever to half choke • Pull starter grip until saw starts and runs Starting Procedures • Quickly depress interlock and throttle – Places saw in run position • Do not pull start rope to its full extension Starting Procedures • Drop starting method – Ensure brake is disengaged – Ensure control lever is in choke – Hold handle with left hand – Hold starter grip with right hand Starting Procedures • Raise saw slightly above waist • Let saw drop in a controlled manner – Pulling starter grip • Repeat until saw fires • Adjust master control valve to half choke Starting Procedures • Continue to drop and pull starter grip until saw fires and runs • Quickly squeeze throttle and interlock – Puts saw in run position • Do not pull start rope to its full extension Procedures • Disengage brake – Rest tip of the saw’s bar on ground or roof – With left hand, keep thumb on handle – Pull back on the chain brake to disengage Procedures • Stopping the Chain – Release throttle to bring saw to idle – Engage chain brake with back of left hand while holding handle • Turn saw off by raising control lever to the stop (top) position • Always place saw in ready to run position when placing back into service – Brake disengaged, throttle trigger interlock depressed and the control lever in the choke position Maintenance Basic • Refuel after use • Refill chain bar oil whenever you refuel • Adjust chain tension ensuring the chain can slide across the bar – Approximately 1/16” gap between bar and chain • Rotate guide bar when chain is removed to extend bar life • Inspect chain for damage – Replace when 3 consecutive teeth or 6 total teeth are missing or when a tie strap is broken • Saw may need a complete tear down to ensure it is thoroughly cleaned of all dirt and debris – Pay extra attention to the cooling fins. Over time they can accumulate “gunk” and cause the saw to overheat. Maintenance Advanced • Recommended tools – Scrench • Stihl combination wrench – Stihl flathead screwdriver – Larger flathead screwdriver – Stihl provided torques style wrench – Cleaning solvent or WD-40 Air Filter System • Set master control lever to full choke • Open the twist lock above and remove the carburetor box cover Air Filter System • Remove filters and check outer butterfly position – Ensure its closed Outer Butterfly • Separate filter components • Clean filters by using compressed air – Blowing from the inside out • In case of stubborn dirt, wash filters with warm soapy water – Rinse from the inside out • Let air dry Felt Prefilter HD Filter Standard Filter Clutch and Chain Assembly • Unscrew the nuts and remove chain sprocket cover – Note side of stamped serial numbers or graphics on chain bar • Bar must be flipped when re-installed Stamped Serial # Chain and Bar Removal • Loosen chain by turning tensioning screw counterclockwise • Once chain starts to sag on the bottom of the bar, remove the bar and chain Chain Tensioning Screw Chain and Bar Cleaning • Use parts cleaner to thoroughly clean chain and bar • Inspect chain and determine if it needs to be out of service. – 3 missing teeth in a row – 6 missing teeth total – 1 broken link • Use a small screwdriver to remove debris from the bar chain guide • Use compressed air to blow excess solvent from the chain and bar and dry with a rag Powerhead Cleaning • Remove the inner side mounting plate by removing the screw adjacent to the tensioning screw • Remove the chain catcher with the Stihl torx wrench Powerhead Cleaning • Removing the E clip from the crank shaft using small screwdriver • Remove clutch drum assembly • Place the needle cage in a cap full of bar oil to lube Clutch Drum Rim Sprocket Needle Cage Washer E-Clip Powerhead Cleaning • Use compressed air to blow as much debris off of the powerhead • Remove the two cover plates using the Stihl torx wrench • Use the parts cleaner to further clean the powerhead – Use caution with the solvent avoiding the carburetor intake • Clean thoroughly • Use compressed air to blow off any excess solvent and dry with a rag Powerhead Cleaning • Clean all parts using the parts cleaner • Use compressed air to blow off excess solvent and dry with a rag • Set aside once cleaned and try to keep everything organized Chainsaw Reassembly • Now reassemble the powerhead in reverse order • Starting with the following – 2 cover plates – Clutch drum assembly • When installing the clutch drum, rotate and apply slight pressure until the oil pump drive spring engages the slot on the outside diameter of the drum • There should be a noticeable connection when the drum catches and drops into place • The slot on the drum is identified with a mark located on the face of the drum Chainsaw Reassembly • Continue reassembling in the following order – – – – – – Chain catcher Inner side plate Bar and chain Sprocket cover Air filter Carburetor box cover Chainsaw Reassembly • Replace bar and chain • Ensure the bar is flipped to the opposite side from where it was initially assembled – This will help with wear over time • Ensure the chain is properly seated in the bar and sprocket Chainsaw Reassembly • Apply tension to the chain by turning the chain tension screw clockwise – Take some of the sag out of the chain • Install the sprocket cover and finger tighten the two nuts Chainsaw Reassembly • Adjust the tension of the chain • Appropriate tension has been applied when: – With a gloved hand, pull the chain upward from the middle of the bar to create a gap equal to the width of a nickels edge being exposed between the chain and bar – With the chain brake off, the chain can be spun around the bar • Use the Scrench to finish tightening the sprocket cover nuts until snug – Do not over tighten Chainsaw Reassembly • Refuel with 2 stroke pre-mix 50:1 fuel • Top off bar oil • Test Run – Ensure adequate chain lubrication by running at full throttle and aiming saw towards the ground – A light spray pattern of oil should begin to form on the ground • Adjust if necessary • Re-adjust chain tension if necessary • Place back into service in the “Ready Run Position” Chainsaw Maintenance • Refer to Stihl Owner’s Manual for further maintenance needs – http://www.stihlusa.co m/stihl_ownersmanual s/044_Manual.pdf Safety • Always wear proper PPE when operating chainsaws. – Minimum- helmet, eye protection, gloves, and hearing protection while performing maintenance • Avoid cutting overhead and inline with body • Maintain a firm grip at all times • Cut at full throttle Safety • Common reactive forces when cutting – Kickback • Occurs when saw chain near upper quadrant of bar nose contacts a solid object causing the saw to fling up and back in an uncontrolled arc – Pushback • Occurs when the chain on the top of the bar is suddenly stopped or caught, driving the saw straight back into the operator – Pull in • Occurs when the chain on the bottom of the bar is suddenly stopped or caught, causing the saw to be pulled forward • Let the saw cool before refueling