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How to Maintain a Lawnmower

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Regular maintenance is key to prolonging the life of your lawnmower. Our experts have compiled this tip-packed guide to help you keep your lawnmower performing at its best and working for years.

Step 1

Detach Sparkplug Lead

Detach Sparkplug Lead

Before performing any maintenance or cleaning procedures on a petrol engine lawnmower, detach the sparkplug lead from the sparkplug; this will prevent accidental engine firing and possible injury. Ensure the engine operation switch is in the OFF position and that the petrol tap is turned off, if applicable. Tip: your sparkplug will need to be replaced every two to three years.

Step 2

Air Filter Maintenance

Air Filter Maintenance

Air filters on lawnmowers collect dust, grit and organic particles, preventing them from entering the engine and causing damage. When the filter becomes full or blocked, the engine will stall or run erratically. Air filters must be cleaned thoroughly or replaced each year, preferably at the beginning of the season. If it is a disposable type filter, purchase and install a replacement.

Step 3

Sponge/Foam Filter Maintenance

Sponge/Foam Filter Maintenance

If your lawnmower’s air filter is a sponge/foam type filter, first locate the filter housing and then remove its retaining screw or bolt. Depending on the lawnmower design, remove either the entire filter housing or just the sponge filter.

Step 4

Wash Sponge Filter

Wash Sponge Filter

While wearing heavy duty rubber gloves, quarter fill a plastic container with petrol (DO NOT USE WATER). Soak the sponge filter in the petrol, turning it over and over and squeezing it dry repeatedly until all the particles and grime are washed off into the petrol. Give the sponge a final hard squeeze to remove as much petrol as possible, then put it back into its house and its place in the engine.

Step 5

Clean Oil Dipstick

Clean Oil Dipstick

With the lawnmower on a level surface, remove the oil dipstick and wipe it clean with a cloth. The dipstick is usually attached to the inside of the oil filler cap or to the side of the engine casing.

Step 6

Check Oil Level

Check Oil Level

Replace the dipstick and remove once more to check the level of the oil. The oil level should be within the marks shown on the dipstick indicator. Top up with fresh engine oil if necessary.

Step 7

Oil Change

Oil Change

The oil should be completely changed after every 25 hours of service. This equates to once a year for the average sized garden. Check the lawnmower manual to determine the capacity of the oil sump on the engine. Choose a plastic container large enough to accept all of the waste oil, which will probably be black and dirty. Run the engine for a couple of minutes to warm up the engine oil, which will thin the oil and make it easier to drain. Detach the sparkplug lead from the sparkplug to prevent accidental engine firing and possible injury. The oil reservoir position is on one side of the engine. Turn the lawnmower onto its side with the oil reservoir cap closest to the ground; it is important you tip it this way to avoid flooding the engine. Prop the lawnmower on its side, place the container underneath the oil filler cap, and remove the cap to allow the oil to drain into the container. Allow a couple of minutes for the oil to completely drain before returning the lawnmower to its up

Step 8

Cutting Blade Maintenance

Cutting Blade Maintenance

Detach the sparkplug lead from the sparkplug to prevent accidental engine firing and possible injury. Use thick protective gloves for this task. Your lawnmower blades will need sharpening once or twice every season depending on the hours of service and the volume of grass cut. To check if your blades need sharpening, simply inspect a patch of freshly cut grass. The grass should be cleanly sliced as if by a scissors. If the cut edges are torn and ragged then your blades need sharpening. Ensure your oil filler cap and your petrol tank cap are firmly secured. Turn your mower onto its side and using the correct sized spanner or socket wrench, loosen the blade attachment nut. Some lawnmower attachment nuts unscrew in a clockwise direction, rather than the normal anti-clockwise direction; refer to the instruction manual.

Step 9

Sharpen Blade

Sharpen Blade

Remove the blades and clamp in a vice for sharpening. Run a sharpening file across the angled edge of the blade to remove any burrs, chips or damage. File from the centre to the outside tip of the blade, always holding the file firmly at the same angle as the angled edge of the blade. Keep filing until the angled face is smooth and the edge of the blade is sharp. Reinstall the blade and tighten the attachment nut.

Step 10

Hose under Mower

Hose under Mower

Keep the underside of your mower clean to ensure proper suction of the cut grass into the grass collector. This can be achieved by rinsing the underside of your mower with a hose after every mowing session.