Chainsaw Maintenance

Keep your edge by following these maintenance tips.

Chainsaws are essential tools. However, nothing is more frustrating than a dull chain or improperly adjusted carburetor. Chainsaws are versatile and they can last for years if they are maintained on a regular schedule.

Sharpening

How do you know when a chain is dull? Two simple indicators will tell you. First, the teeth on chains are designed to cut by “biting” into the wood. Depth gauges, located in front of each tooth, regulate the size of this “bite” and determine how much wood is cut each pass. A sharp chain will “self feed” and the teeth will cut as deep as the depth gauge will allow. You can feel this when you are cutting—you need to apply just a small amount of pressure and the chain will cut on its own. When chains are dull, they do not “self feed” and you have to push the chain into the wood. Second, sharp chains will cut large (up to 0.25 inch) squarish chips. However, dull chains that do not bite will cut small chips that resemble sawdust.

When sharpening your chain, place the saw on a sturdy, well-lit surface. Wear tight-fitting leather gloves so that you are not cut when handling the chain. Place a wood block underneath the bar to keep the saw from teetering. Next, ensure that the chain is properly tensioned. If it is too loose, the chain will wobble and you will not be able to file it correctly. However, if it is too tight you will not be able to pull it around the bar and sharpen the other teeth.

Many file guides are available that will assist you when sharpening a chain. They hold the chain and align the file at the correct angle. Also, some file guides have locking mechanisms that automatically stop the chain at the next tooth.

Many chain sizes are available and they have various cutting depths. Therefore, no standard file size is available to sharpen all chains. Consult your owners’ manual or a service technician to determine which file size is right for your chain.

The working corner is the part of the tooth that does most of the cutting. Align your file so that it cuts when you stroke towards the outside of the tooth (files only work in one direction). Grasp the file with both hands and make a firm stroke. Release the pressure on the return and make another stroke.

  1. File the top plate. This angle ranges from 25 to 35°, most guides have 30 to 35° angle scribed on them.
  2. File the side plate. Most chains have a side plate angle around 85°.
  3. Check the cutting angle and working corner. This angle should automatically form when you file the top plate and side plate. If correctly filed, your cutting angle will be consistent across the entire cutting edge. Usually this angle is around 60°.

File the chain until any nicks and damages are removed. Look at the corner of the cutting blades on the teeth. If you see a clean, thin chrome edge, the chain is sharp. Advance the chain to the next tooth. Sharpen all of the teeth on one side before you change the guide angle to work on the teeth on the other side.

While a sharp chain is your primary concern, you must maintain the other saw components to prolong the life of the saw. These components, when working properly, also ensure that your saw will perform trouble-free.

Fuel system

Always use clean fuel that is free of water or other contaminants. Chainsaws use fuel and oil mixes in differing ratios depending on the manufacturer. Check the owners’ manual to verify which mix you should use. Label your fuel cans. With blowers, trimmers and other small engines around it is easy to confuse one gas can with another one.

Fuel filters help clear contaminants, but when they get clogged fuel flow is restricted. During heavy-use periods, clean your fuel filter weekly and replace it as needed.

Clean the fuel tanks about once a month by pouring out the fuel and inspecting the tank for dirt and debris. Do not store chainsaws directly on cool surfaces such as concrete. The air in the fuel tank will cool and condense, causing moisture to entire the fuel.

Chain system

Besides sharpening your chain, you should constantly check the chain system for looseness. When idle, the chain should slightly hang from the bar. The chain guides (tangs) should still be sticking mostly into the bar. When the saw is off and the chain brake released, you should be able to manually feed the chain around the bar without difficulty. Check the bar-retaining nuts regularly during operation, the constant vibration will loosen them.

Visually inspect the bar before each use. Look along the length for any curvature or bends. Inspect the trough in which the drive link tangs rest to make sure that it is clean and not damaged. If the trough is pinched or too wide, insert a steel shim that is 0.004 inch thicker than the drive link tangs. Use a ball peen hammer to adjust the trough width by tapping on the bar or driving the shim through pinched spots.

Lubricate roller tips as directed by the manufacturer. Inspect the roller side plate for burs and remove them with a flat file. Look for damage and wear, replace if necessary.

Remove the bar-retaining nuts and cover to expose the chain-drive sprocket. Inspect the teeth on the sprocket for damage and remove any debris. With the clutch disengaged, rotate the clutch drum and sprocket. Look for any discontinuity that might indicate a problem. Inspect the drum and shoe for glazing that is caused by slippage. You can remove the glazing with a wire brush. Remove the clutch drum and repack the bearings periodically. If you live in wet environments or the saw gets drenched with water, remove the clutch drum and thoroughly dry it. After every use, remove the chain and bar and clean them to remove dust, dirt and other materials.

Check the level of bar and chain oil constantly during use. You will be surprised how much oil you will use. If you run out there is no warning light other than the smoke rising from the chain. The excess heat can cause severe damage to the bar, chain and sprocket.

Air filter

Because chainsaws are always operated in dusty conditions, you must clean the air filter after every use. Before you expose the air filter, thoroughly clean the outside of the saw and move it to an area away from sawdust or other materials that could fall into the carburetor. Remove the filter and clean it with an air compressor or as recommended in your owners’ manual. During periods of heavy use you should replace the air filter weekly.

Engine

Consult chainsaw service technicians for most engine work. They have the tools and know-how to evaluate all of the components. However, here are 3 maintenance tasks that anyone can perform.

Spark plugs. If you are having trouble starting your saw, check the plug and plug wire. Replace your plugs every year and set the gap to manufacturers specifications.

Carburetor. Minor adjustments can make a remarkable difference. Every time you use your saw, evaluate how it is idling, how it accelerates and how it retains its top speed. If the engine is sluggish or cuts out, consult your owner’s manual for carburetor settings and adjustments.

Muffler. Clean the muffler and exhaust ports monthly. Use a scraper to remove black carbon deposits. Clean the muffler guard daily and inspect it for damage weekly.

Pull cord

Visually inspect the pull cord for any fraying or cuts before use. Inspect the toggle to ensure that the cord is securely attached. If any of these items are damaged, fix them now under your terms or you may experience a failure in the field.

Off-season storage

If you store your chainsaw for a period of 30 days or more, you need to follow special precautions to limit exposure. Drain all fuel from the tank. Next, drain all fuel from the line and carburetor by starting the saw and running it until it stops. Drain all oil and remove the bar and chain. Store the chain in an airtight container that is fill with oil so that the entire chain is submerged. Apply a light coating of oil to the bar and wrap it in paper. Clean the exterior and interior of the saw. Remove the spark plug and apply a rust inhibitor into the combustion chamber. Replace spark plug and pull the starter rope slowly several times to distribute the inhibitor over the cylinder.

There is nothing more frustrating than a saw that is not operating properly. Minor tree removals can drag on for hours if you are fighting a dull chain or water in the fuel system. Always carry extra chains, if your saw contacts soil or any other hard surface it will instantly become useless. Also, pay special attention to storage procedures. You will be rewarded with trouble-free operation when you start your saw again. Finally, follow all of these tips and keep a preventative maintenance calendar current by adding any information regarding replacements and cleaning. Chainsaws are a simple piece of equipment that can provide you with years of service. However, they can be your worst nightmare if you don’t keep the edge.

Technical credit: Michael McCaskey, Bill Combs, Frank Bretthauer, Chain Saw Service Manual, 10th edition, Intertec Publishing Corp.

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© 2016 Penton Media Inc.

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