Chainsaws are a tool that the majority of farmers now have in their arsenal, but are generally only used sporadically on most farms. The trusty chainsaw should be fully serviced at least once a year, or more frequently, depending usage. We outline the areas worth taking a look at before the saw is brought out to tackle some winter tasks.

1. Spark plug

It’s good practice to replace the spark plug at every service. A worn-out spark plug will leave the chainsaw hard to start, or, worst-case scenario, may be the reason it fails to start. A replacement spark plug will only cost around €5. When replacing the existing spark plug, take note of the condition of the spark plug – it can tell a lot about how the engine is running. If the porcelain insulator is cracked, an electrode may be damaged or burnt. A grey colouring on the spark plug may indicate damage to the piston. This grey discolouration is a result of aluminium burning in the cylinder.

2. Air and fuel filter

It’s quite common for chainsaws to be left unused for long periods of time. During these prolonged periods, by rights, the fuel tank should be left empty. It’s not uncommon for constituents of the two-stroke fuel mix ingredients to evaporate and leave behind a jelly-like residue. If this happens, it may clog up the carburettor. In most cases, carburettor cleaner will resolve the issue, but the worst-case scenario is replacement. If the saw hasn’t been used for a number of months and there’s fuel in it, it’s good practice to empty the fuel tank and replace with fresh fuel.

The air filter should be removed and cleaned on a regular basis. The vents should also be cleaned out to ensure the air intake is not blocked. Blockages here can cause the saw to overheat. A blocked air filter will restrict the power, cause the saw to burn more fuel and will smother the spark plug. A blocked air intake will also restrict the air getting to the carburettor, which will affect the saw’s performance. Both the fuel and air filter should be replaced at every service. A typical fuel filter will cost around €5 to €6, with air filters generally costing less than €15.

3. Sharpening the chain

The volume of work you are doing with the saw will determine how often the chain needs to be sharpened. As a rule of thumb, if you find yourself leaning on the chainsaw to make it cut, then you need to sharpen the chain. A blunt chain takes longer to cut, uses more fuel and, over a period of time, will lead to chain damage and premature bar and sprocket wear. Remember, a chain can instantly lose its edge if it makes contact with clay or a stone.

Regardless of the sharpening method, each cutting tooth on the chain will have a diagonal line, called a witness mark. This indicates the sharpening angle and marks the end of the life of the chain when filed to this point.

Chains can be sharpened manually using a file or using an electric sharpener. An electric sharpener requires the chain to be removed from the guide bar. A simple round file is the most basic option. However, there is a two-in-one tool available that sharpens both the cutters and depth gauge (rakers) simultaneously. This file eliminates the need to return to the yard for sharpening and once familiar with the process, can be as quick as removing the chain for use with an electric sharpener.

First off, it’s important to identify the chain size, which will determine the size of the file needed – it’s not a one-size-fits-all scenario. A chain that has been sharpened unevenly or at the incorrect angle will not cut straight. To sharpen, the file/two-in-one tool should be held level and at the correct angle. It then needs to be drawn from the inside of the cutter to the outside of the cutter. Start by sharpening all the cutters on one side of the chain, then file the cutters on the opposite side. It should be relatively easy to see where you started, as the sharpened cutters tend to be shiny with traces of filings. For an even cut and even wear, each cutter should receive the same number of strokes with the file. As a chain is sharpened, its depth gauges need to be lowered. The two–in-one tool does this automatically, but those using a standard round file will need to follow with a flat file and lower the rakers separately.

Too low and the saw will be biting too much into the timber, causing it to jump, or if too high, the chainsaw will fail to cut. If in doubt, get the chain professionally sharpened, which will only cost around €10.

4. Guide bar, tension and brakes

The guide bar is a wearing part and is often overlooked. The track on which the chain runs needs to be kept clean for proper lubrication to take place. There is a bearing and sprocket at the top of each guide bar on which the chain rotates. This sprocket should rotate freely, and the bearing needs to be greased regularly. The guide bar itself will occasionally have to be replaced. If the guide bar channel has widened to the point that the chain has become loose, then it will need to be replaced or turned upside down. The top side will naturally wear more, so when wear becomes noticeable, turn it upside down to get that bit extra out of it before replacement.

Chain tension is important, too tight and it will not move freely on the guide bar; too loose and it could come off the bar. It should be tightened to the point it is resting against the bottom side of the guide bar. Run the saw for a few minutes and recheck the tension and adjust if necessary. The chain brake is a safety feature that is of critical importance on any chainsaw, and it must be functional. It’s essentially a steel band around the clutch drum. When activated in an emergency situation, the band tightens on the clutch drum and stops the chain immediately. A saw with no chain brake should not be used.

5. Lubrication

Every time you fill the chainsaw with two-stroke, you should also top up the chain oil tank. It’s important that operators use proper chain oil and not waste oil lying around the workshop. Waste oil has a high sulphur content and reduced lubrication qualities.

Dedicated chain oil has the necessary cling qualities, meaning it’s not flung off the chain as quick as it is applied. Proper chainsaw oil is readily available in most hardware stores, and is critical for the life of your chainsaw. The fuel mix is also important. A recognised brand of two-stroke oil should be used and mixed with the petrol at the correct manufacturer’s ratio.

The correct safety gear

Check that all guards are intact. A simple rule when operating a chainsaw is gear up before you go near the saw. The correct personal protective equipment (PPE) needs to be worn at all times when the saw is in operation. This includes safety helmet with a faceguard, earmuffs, gloves, chainsaw trousers and safety steel-toe boots. A quality set of the above will cost in the region of €180 to €200. If minded, it will last for many years and has the potential to save enormous medical fees in the event of an accident.

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